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  99. <li><a class="reference internal" href="#collections-abstract-base-classes">Collections Abstract Base Classes</a></li>

  100. <li><a class="reference internal" href="#collections-abstract-base-classes-detailed-descriptions">Collections Abstract Base Classes – Detailed Descriptions</a></li>

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  194.   <section id="module-collections.abc">

  195. <span id="collections-abc-abstract-base-classes-for-containers"></span><h1><a class="reference internal" href="#module-collections.abc" title="collections.abc: Abstract base classes for containers"><code class="xref py py-mod docutils literal notranslate"><span class="pre">collections.abc</span></code></a> — Abstract Base Classes for Containers<a class="headerlink" href="#module-collections.abc" title="Link to this heading">¶</a></h1>

  196. <div class="versionadded">

  197. <p><span class="versionmodified added">New in version 3.3: </span>Formerly, this module was part of the <a class="reference internal" href="collections.html#module-collections" title="collections: Container datatypes"><code class="xref py py-mod docutils literal notranslate"><span class="pre">collections</span></code></a> module.</p>

  198. </div>

  199. <p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.12/Lib/_collections_abc.py">Lib/_collections_abc.py</a></p>

  200. <hr class="docutils" />

  201. <p>This module provides <a class="reference internal" href="../glossary.html#term-abstract-base-class"><span class="xref std std-term">abstract base classes</span></a> that

  202. can be used to test whether a class provides a particular interface; for

  203. example, whether it is <a class="reference internal" href="../glossary.html#term-hashable"><span class="xref std std-term">hashable</span></a> or whether it is a <a class="reference internal" href="../glossary.html#term-mapping"><span class="xref std std-term">mapping</span></a>.</p>

  204. <p>An <a class="reference internal" href="functions.html#issubclass" title="issubclass"><code class="xref py py-func docutils literal notranslate"><span class="pre">issubclass()</span></code></a> or <a class="reference internal" href="functions.html#isinstance" title="isinstance"><code class="xref py py-func docutils literal notranslate"><span class="pre">isinstance()</span></code></a> test for an interface works in one

  205. of three ways.</p>

  206. <p>1) A newly written class can inherit directly from one of the

  207. abstract base classes.  The class must supply the required abstract

  208. methods.  The remaining mixin methods come from inheritance and can be

  209. overridden if desired.  Other methods may be added as needed:</p>

  210. <div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">C</span><span class="p">(</span><span class="n">Sequence</span><span class="p">):</span>                      <span class="c1"># Direct inheritance</span>

  211.     <span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="o">...</span>             <span class="c1"># Extra method not required by the ABC</span>

  212.     <span class="k">def</span> <span class="fm">__getitem__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">index</span><span class="p">):</span>  <span class="o">...</span>  <span class="c1"># Required abstract method</span>

  213.     <span class="k">def</span> <span class="fm">__len__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>  <span class="o">...</span>             <span class="c1"># Required abstract method</span>

  214.     <span class="k">def</span> <span class="nf">count</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">value</span><span class="p">):</span> <span class="o">...</span>         <span class="c1"># Optionally override a mixin method</span>

  215. </pre></div>

  216. </div>

  217. <div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="nb">issubclass</span><span class="p">(</span><span class="n">C</span><span class="p">,</span> <span class="n">Sequence</span><span class="p">)</span>

  218. <span class="go">True</span>

  219. <span class="gp">&gt;&gt;&gt; </span><span class="nb">isinstance</span><span class="p">(</span><span class="n">C</span><span class="p">(),</span> <span class="n">Sequence</span><span class="p">)</span>

  220. <span class="go">True</span>

  221. </pre></div>

  222. </div>

  223. <p>2) Existing classes and built-in classes can be registered as “virtual

  224. subclasses” of the ABCs.  Those classes should define the full API

  225. including all of the abstract methods and all of the mixin methods.

  226. This lets users rely on <a class="reference internal" href="functions.html#issubclass" title="issubclass"><code class="xref py py-func docutils literal notranslate"><span class="pre">issubclass()</span></code></a> or <a class="reference internal" href="functions.html#isinstance" title="isinstance"><code class="xref py py-func docutils literal notranslate"><span class="pre">isinstance()</span></code></a> tests

  227. to determine whether the full interface is supported.  The exception to

  228. this rule is for methods that are automatically inferred from the rest

  229. of the API:</p>

  230. <div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">D</span><span class="p">:</span>                                 <span class="c1"># No inheritance</span>

  231.     <span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="o">...</span>              <span class="c1"># Extra method not required by the ABC</span>

  232.     <span class="k">def</span> <span class="fm">__getitem__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">index</span><span class="p">):</span>  <span class="o">...</span>   <span class="c1"># Abstract method</span>

  233.     <span class="k">def</span> <span class="fm">__len__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>  <span class="o">...</span>              <span class="c1"># Abstract method</span>

  234.     <span class="k">def</span> <span class="nf">count</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">value</span><span class="p">):</span> <span class="o">...</span>          <span class="c1"># Mixin method</span>

  235.     <span class="k">def</span> <span class="nf">index</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">value</span><span class="p">):</span> <span class="o">...</span>          <span class="c1"># Mixin method</span>

  236. 

  237. <span class="n">Sequence</span><span class="o">.</span><span class="n">register</span><span class="p">(</span><span class="n">D</span><span class="p">)</span>                     <span class="c1"># Register instead of inherit</span>

  238. </pre></div>

  239. </div>

  240. <div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="nb">issubclass</span><span class="p">(</span><span class="n">D</span><span class="p">,</span> <span class="n">Sequence</span><span class="p">)</span>

  241. <span class="go">True</span>

  242. <span class="gp">&gt;&gt;&gt; </span><span class="nb">isinstance</span><span class="p">(</span><span class="n">D</span><span class="p">(),</span> <span class="n">Sequence</span><span class="p">)</span>

  243. <span class="go">True</span>

  244. </pre></div>

  245. </div>

  246. <p>In this example, class <code class="xref py py-class docutils literal notranslate"><span class="pre">D</span></code> does not need to define

  247. <code class="docutils literal notranslate"><span class="pre">__contains__</span></code>, <code class="docutils literal notranslate"><span class="pre">__iter__</span></code>, and <code class="docutils literal notranslate"><span class="pre">__reversed__</span></code> because the

  248. <a class="reference internal" href="../reference/expressions.html#comparisons"><span class="std std-ref">in-operator</span></a>, the <a class="reference internal" href="../glossary.html#term-iterable"><span class="xref std std-term">iteration</span></a>

  249. logic, and the <a class="reference internal" href="functions.html#reversed" title="reversed"><code class="xref py py-func docutils literal notranslate"><span class="pre">reversed()</span></code></a> function automatically fall back to

  250. using <code class="docutils literal notranslate"><span class="pre">__getitem__</span></code> and <code class="docutils literal notranslate"><span class="pre">__len__</span></code>.</p>

  251. <p>3) Some simple interfaces are directly recognizable by the presence of

  252. the required methods (unless those methods have been set to

  253. <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a>):</p>

  254. <div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">E</span><span class="p">:</span>

  255.     <span class="k">def</span> <span class="fm">__iter__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="o">...</span>

  256.     <span class="k">def</span> <span class="fm">__next__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="o">...</span>

  257. </pre></div>

  258. </div>

  259. <div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="nb">issubclass</span><span class="p">(</span><span class="n">E</span><span class="p">,</span> <span class="n">Iterable</span><span class="p">)</span>

  260. <span class="go">True</span>

  261. <span class="gp">&gt;&gt;&gt; </span><span class="nb">isinstance</span><span class="p">(</span><span class="n">E</span><span class="p">(),</span> <span class="n">Iterable</span><span class="p">)</span>

  262. <span class="go">True</span>

  263. </pre></div>

  264. </div>

  265. <p>Complex interfaces do not support this last technique because an

  266. interface is more than just the presence of method names.  Interfaces

  267. specify semantics and relationships between methods that cannot be

  268. inferred solely from the presence of specific method names.  For

  269. example, knowing that a class supplies <code class="docutils literal notranslate"><span class="pre">__getitem__</span></code>, <code class="docutils literal notranslate"><span class="pre">__len__</span></code>, and

  270. <code class="docutils literal notranslate"><span class="pre">__iter__</span></code> is insufficient for distinguishing a <a class="reference internal" href="#collections.abc.Sequence" title="collections.abc.Sequence"><code class="xref py py-class docutils literal notranslate"><span class="pre">Sequence</span></code></a> from

  271. a <a class="reference internal" href="#collections.abc.Mapping" title="collections.abc.Mapping"><code class="xref py py-class docutils literal notranslate"><span class="pre">Mapping</span></code></a>.</p>

  272. <div class="versionadded">

  273. <p><span class="versionmodified added">New in version 3.9: </span>These abstract classes now support <code class="docutils literal notranslate"><span class="pre">[]</span></code>. See <a class="reference internal" href="stdtypes.html#types-genericalias"><span class="std std-ref">Generic Alias Type</span></a>

  274. and <span class="target" id="index-0"></span><a class="pep reference external" href="https://peps.python.org/pep-0585/"><strong>PEP 585</strong></a>.</p>

  275. </div>

  276. <section id="collections-abstract-base-classes">

  277. <span id="id1"></span><h2>Collections Abstract Base Classes<a class="headerlink" href="#collections-abstract-base-classes" title="Link to this heading">¶</a></h2>

  278. <p>The collections module offers the following <a class="reference internal" href="../glossary.html#term-abstract-base-class"><span class="xref std std-term">ABCs</span></a>:</p>

  279. <table class="docutils align-default">

  280. <thead>

  281. <tr class="row-odd"><th class="head"><p>ABC</p></th>

  282. <th class="head"><p>Inherits from</p></th>

  283. <th class="head"><p>Abstract Methods</p></th>

  284. <th class="head"><p>Mixin Methods</p></th>

  285. </tr>

  286. </thead>

  287. <tbody>

  288. <tr class="row-even"><td><p><a class="reference internal" href="#collections.abc.Container" title="collections.abc.Container"><code class="xref py py-class docutils literal notranslate"><span class="pre">Container</span></code></a> <a class="footnote-reference brackets" href="#id18" id="id2" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  289. <td></td>

  290. <td><p><code class="docutils literal notranslate"><span class="pre">__contains__</span></code></p></td>

  291. <td></td>

  292. </tr>

  293. <tr class="row-odd"><td><p><a class="reference internal" href="#collections.abc.Hashable" title="collections.abc.Hashable"><code class="xref py py-class docutils literal notranslate"><span class="pre">Hashable</span></code></a> <a class="footnote-reference brackets" href="#id18" id="id3" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  294. <td></td>

  295. <td><p><code class="docutils literal notranslate"><span class="pre">__hash__</span></code></p></td>

  296. <td></td>

  297. </tr>

  298. <tr class="row-even"><td><p><a class="reference internal" href="#collections.abc.Iterable" title="collections.abc.Iterable"><code class="xref py py-class docutils literal notranslate"><span class="pre">Iterable</span></code></a> <a class="footnote-reference brackets" href="#id18" id="id4" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a> <a class="footnote-reference brackets" href="#id19" id="id5" role="doc-noteref"><span class="fn-bracket">[</span>2<span class="fn-bracket">]</span></a></p></td>

  299. <td></td>

  300. <td><p><code class="docutils literal notranslate"><span class="pre">__iter__</span></code></p></td>

  301. <td></td>

  302. </tr>

  303. <tr class="row-odd"><td><p><a class="reference internal" href="#collections.abc.Iterator" title="collections.abc.Iterator"><code class="xref py py-class docutils literal notranslate"><span class="pre">Iterator</span></code></a> <a class="footnote-reference brackets" href="#id18" id="id6" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  304. <td><p><a class="reference internal" href="#collections.abc.Iterable" title="collections.abc.Iterable"><code class="xref py py-class docutils literal notranslate"><span class="pre">Iterable</span></code></a></p></td>

  305. <td><p><code class="docutils literal notranslate"><span class="pre">__next__</span></code></p></td>

  306. <td><p><code class="docutils literal notranslate"><span class="pre">__iter__</span></code></p></td>

  307. </tr>

  308. <tr class="row-even"><td><p><a class="reference internal" href="#collections.abc.Reversible" title="collections.abc.Reversible"><code class="xref py py-class docutils literal notranslate"><span class="pre">Reversible</span></code></a> <a class="footnote-reference brackets" href="#id18" id="id7" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  309. <td><p><a class="reference internal" href="#collections.abc.Iterable" title="collections.abc.Iterable"><code class="xref py py-class docutils literal notranslate"><span class="pre">Iterable</span></code></a></p></td>

  310. <td><p><code class="docutils literal notranslate"><span class="pre">__reversed__</span></code></p></td>

  311. <td></td>

  312. </tr>

  313. <tr class="row-odd"><td><p><a class="reference internal" href="#collections.abc.Generator" title="collections.abc.Generator"><code class="xref py py-class docutils literal notranslate"><span class="pre">Generator</span></code></a>  <a class="footnote-reference brackets" href="#id18" id="id8" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  314. <td><p><a class="reference internal" href="#collections.abc.Iterator" title="collections.abc.Iterator"><code class="xref py py-class docutils literal notranslate"><span class="pre">Iterator</span></code></a></p></td>

  315. <td><p><code class="docutils literal notranslate"><span class="pre">send</span></code>, <code class="docutils literal notranslate"><span class="pre">throw</span></code></p></td>

  316. <td><p><code class="docutils literal notranslate"><span class="pre">close</span></code>, <code class="docutils literal notranslate"><span class="pre">__iter__</span></code>, <code class="docutils literal notranslate"><span class="pre">__next__</span></code></p></td>

  317. </tr>

  318. <tr class="row-even"><td><p><a class="reference internal" href="#collections.abc.Sized" title="collections.abc.Sized"><code class="xref py py-class docutils literal notranslate"><span class="pre">Sized</span></code></a>  <a class="footnote-reference brackets" href="#id18" id="id9" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  319. <td></td>

  320. <td><p><code class="docutils literal notranslate"><span class="pre">__len__</span></code></p></td>

  321. <td></td>

  322. </tr>

  323. <tr class="row-odd"><td><p><a class="reference internal" href="#collections.abc.Callable" title="collections.abc.Callable"><code class="xref py py-class docutils literal notranslate"><span class="pre">Callable</span></code></a>  <a class="footnote-reference brackets" href="#id18" id="id10" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  324. <td></td>

  325. <td><p><code class="docutils literal notranslate"><span class="pre">__call__</span></code></p></td>

  326. <td></td>

  327. </tr>

  328. <tr class="row-even"><td><p><a class="reference internal" href="#collections.abc.Collection" title="collections.abc.Collection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Collection</span></code></a>  <a class="footnote-reference brackets" href="#id18" id="id11" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  329. <td><p><a class="reference internal" href="#collections.abc.Sized" title="collections.abc.Sized"><code class="xref py py-class docutils literal notranslate"><span class="pre">Sized</span></code></a>,

  330. <a class="reference internal" href="#collections.abc.Iterable" title="collections.abc.Iterable"><code class="xref py py-class docutils literal notranslate"><span class="pre">Iterable</span></code></a>,

  331. <a class="reference internal" href="#collections.abc.Container" title="collections.abc.Container"><code class="xref py py-class docutils literal notranslate"><span class="pre">Container</span></code></a></p></td>

  332. <td><p><code class="docutils literal notranslate"><span class="pre">__contains__</span></code>,

  333. <code class="docutils literal notranslate"><span class="pre">__iter__</span></code>,

  334. <code class="docutils literal notranslate"><span class="pre">__len__</span></code></p></td>

  335. <td></td>

  336. </tr>

  337. <tr class="row-odd"><td><p><a class="reference internal" href="#collections.abc.Sequence" title="collections.abc.Sequence"><code class="xref py py-class docutils literal notranslate"><span class="pre">Sequence</span></code></a></p></td>

  338. <td><p><a class="reference internal" href="#collections.abc.Reversible" title="collections.abc.Reversible"><code class="xref py py-class docutils literal notranslate"><span class="pre">Reversible</span></code></a>,

  339. <a class="reference internal" href="#collections.abc.Collection" title="collections.abc.Collection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Collection</span></code></a></p></td>

  340. <td><p><code class="docutils literal notranslate"><span class="pre">__getitem__</span></code>,

  341. <code class="docutils literal notranslate"><span class="pre">__len__</span></code></p></td>

  342. <td><p><code class="docutils literal notranslate"><span class="pre">__contains__</span></code>, <code class="docutils literal notranslate"><span class="pre">__iter__</span></code>, <code class="docutils literal notranslate"><span class="pre">__reversed__</span></code>,

  343. <code class="docutils literal notranslate"><span class="pre">index</span></code>, and <code class="docutils literal notranslate"><span class="pre">count</span></code></p></td>

  344. </tr>

  345. <tr class="row-even"><td><p><a class="reference internal" href="#collections.abc.MutableSequence" title="collections.abc.MutableSequence"><code class="xref py py-class docutils literal notranslate"><span class="pre">MutableSequence</span></code></a></p></td>

  346. <td><p><a class="reference internal" href="#collections.abc.Sequence" title="collections.abc.Sequence"><code class="xref py py-class docutils literal notranslate"><span class="pre">Sequence</span></code></a></p></td>

  347. <td><p><code class="docutils literal notranslate"><span class="pre">__getitem__</span></code>,

  348. <code class="docutils literal notranslate"><span class="pre">__setitem__</span></code>,

  349. <code class="docutils literal notranslate"><span class="pre">__delitem__</span></code>,

  350. <code class="docutils literal notranslate"><span class="pre">__len__</span></code>,

  351. <code class="docutils literal notranslate"><span class="pre">insert</span></code></p></td>

  352. <td><p>Inherited <a class="reference internal" href="#collections.abc.Sequence" title="collections.abc.Sequence"><code class="xref py py-class docutils literal notranslate"><span class="pre">Sequence</span></code></a> methods and

  353. <code class="docutils literal notranslate"><span class="pre">append</span></code>, <code class="docutils literal notranslate"><span class="pre">clear</span></code>, <code class="docutils literal notranslate"><span class="pre">reverse</span></code>, <code class="docutils literal notranslate"><span class="pre">extend</span></code>,

  354. <code class="docutils literal notranslate"><span class="pre">pop</span></code>, <code class="docutils literal notranslate"><span class="pre">remove</span></code>, and <code class="docutils literal notranslate"><span class="pre">__iadd__</span></code></p></td>

  355. </tr>

  356. <tr class="row-odd"><td><p><a class="reference internal" href="#collections.abc.ByteString" title="collections.abc.ByteString"><code class="xref py py-class docutils literal notranslate"><span class="pre">ByteString</span></code></a></p></td>

  357. <td><p><a class="reference internal" href="#collections.abc.Sequence" title="collections.abc.Sequence"><code class="xref py py-class docutils literal notranslate"><span class="pre">Sequence</span></code></a></p></td>

  358. <td><p><code class="docutils literal notranslate"><span class="pre">__getitem__</span></code>,

  359. <code class="docutils literal notranslate"><span class="pre">__len__</span></code></p></td>

  360. <td><p>Inherited <a class="reference internal" href="#collections.abc.Sequence" title="collections.abc.Sequence"><code class="xref py py-class docutils literal notranslate"><span class="pre">Sequence</span></code></a> methods</p></td>

  361. </tr>

  362. <tr class="row-even"><td><p><a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate"><span class="pre">Set</span></code></a></p></td>

  363. <td><p><a class="reference internal" href="#collections.abc.Collection" title="collections.abc.Collection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Collection</span></code></a></p></td>

  364. <td><p><code class="docutils literal notranslate"><span class="pre">__contains__</span></code>,

  365. <code class="docutils literal notranslate"><span class="pre">__iter__</span></code>,

  366. <code class="docutils literal notranslate"><span class="pre">__len__</span></code></p></td>

  367. <td><p><code class="docutils literal notranslate"><span class="pre">__le__</span></code>, <code class="docutils literal notranslate"><span class="pre">__lt__</span></code>, <code class="docutils literal notranslate"><span class="pre">__eq__</span></code>, <code class="docutils literal notranslate"><span class="pre">__ne__</span></code>,

  368. <code class="docutils literal notranslate"><span class="pre">__gt__</span></code>, <code class="docutils literal notranslate"><span class="pre">__ge__</span></code>, <code class="docutils literal notranslate"><span class="pre">__and__</span></code>, <code class="docutils literal notranslate"><span class="pre">__or__</span></code>,

  369. <code class="docutils literal notranslate"><span class="pre">__sub__</span></code>, <code class="docutils literal notranslate"><span class="pre">__xor__</span></code>, and <code class="docutils literal notranslate"><span class="pre">isdisjoint</span></code></p></td>

  370. </tr>

  371. <tr class="row-odd"><td><p><a class="reference internal" href="#collections.abc.MutableSet" title="collections.abc.MutableSet"><code class="xref py py-class docutils literal notranslate"><span class="pre">MutableSet</span></code></a></p></td>

  372. <td><p><a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate"><span class="pre">Set</span></code></a></p></td>

  373. <td><p><code class="docutils literal notranslate"><span class="pre">__contains__</span></code>,

  374. <code class="docutils literal notranslate"><span class="pre">__iter__</span></code>,

  375. <code class="docutils literal notranslate"><span class="pre">__len__</span></code>,

  376. <code class="docutils literal notranslate"><span class="pre">add</span></code>,

  377. <code class="docutils literal notranslate"><span class="pre">discard</span></code></p></td>

  378. <td><p>Inherited <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate"><span class="pre">Set</span></code></a> methods and

  379. <code class="docutils literal notranslate"><span class="pre">clear</span></code>, <code class="docutils literal notranslate"><span class="pre">pop</span></code>, <code class="docutils literal notranslate"><span class="pre">remove</span></code>, <code class="docutils literal notranslate"><span class="pre">__ior__</span></code>,

  380. <code class="docutils literal notranslate"><span class="pre">__iand__</span></code>, <code class="docutils literal notranslate"><span class="pre">__ixor__</span></code>, and <code class="docutils literal notranslate"><span class="pre">__isub__</span></code></p></td>

  381. </tr>

  382. <tr class="row-even"><td><p><a class="reference internal" href="#collections.abc.Mapping" title="collections.abc.Mapping"><code class="xref py py-class docutils literal notranslate"><span class="pre">Mapping</span></code></a></p></td>

  383. <td><p><a class="reference internal" href="#collections.abc.Collection" title="collections.abc.Collection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Collection</span></code></a></p></td>

  384. <td><p><code class="docutils literal notranslate"><span class="pre">__getitem__</span></code>,

  385. <code class="docutils literal notranslate"><span class="pre">__iter__</span></code>,

  386. <code class="docutils literal notranslate"><span class="pre">__len__</span></code></p></td>

  387. <td><p><code class="docutils literal notranslate"><span class="pre">__contains__</span></code>, <code class="docutils literal notranslate"><span class="pre">keys</span></code>, <code class="docutils literal notranslate"><span class="pre">items</span></code>, <code class="docutils literal notranslate"><span class="pre">values</span></code>,

  388. <code class="docutils literal notranslate"><span class="pre">get</span></code>, <code class="docutils literal notranslate"><span class="pre">__eq__</span></code>, and <code class="docutils literal notranslate"><span class="pre">__ne__</span></code></p></td>

  389. </tr>

  390. <tr class="row-odd"><td><p><a class="reference internal" href="#collections.abc.MutableMapping" title="collections.abc.MutableMapping"><code class="xref py py-class docutils literal notranslate"><span class="pre">MutableMapping</span></code></a></p></td>

  391. <td><p><a class="reference internal" href="#collections.abc.Mapping" title="collections.abc.Mapping"><code class="xref py py-class docutils literal notranslate"><span class="pre">Mapping</span></code></a></p></td>

  392. <td><p><code class="docutils literal notranslate"><span class="pre">__getitem__</span></code>,

  393. <code class="docutils literal notranslate"><span class="pre">__setitem__</span></code>,

  394. <code class="docutils literal notranslate"><span class="pre">__delitem__</span></code>,

  395. <code class="docutils literal notranslate"><span class="pre">__iter__</span></code>,

  396. <code class="docutils literal notranslate"><span class="pre">__len__</span></code></p></td>

  397. <td><p>Inherited <a class="reference internal" href="#collections.abc.Mapping" title="collections.abc.Mapping"><code class="xref py py-class docutils literal notranslate"><span class="pre">Mapping</span></code></a> methods and

  398. <code class="docutils literal notranslate"><span class="pre">pop</span></code>, <code class="docutils literal notranslate"><span class="pre">popitem</span></code>, <code class="docutils literal notranslate"><span class="pre">clear</span></code>, <code class="docutils literal notranslate"><span class="pre">update</span></code>,

  399. and <code class="docutils literal notranslate"><span class="pre">setdefault</span></code></p></td>

  400. </tr>

  401. <tr class="row-even"><td><p><a class="reference internal" href="#collections.abc.MappingView" title="collections.abc.MappingView"><code class="xref py py-class docutils literal notranslate"><span class="pre">MappingView</span></code></a></p></td>

  402. <td><p><a class="reference internal" href="#collections.abc.Sized" title="collections.abc.Sized"><code class="xref py py-class docutils literal notranslate"><span class="pre">Sized</span></code></a></p></td>

  403. <td></td>

  404. <td><p><code class="docutils literal notranslate"><span class="pre">__len__</span></code></p></td>

  405. </tr>

  406. <tr class="row-odd"><td><p><a class="reference internal" href="#collections.abc.ItemsView" title="collections.abc.ItemsView"><code class="xref py py-class docutils literal notranslate"><span class="pre">ItemsView</span></code></a></p></td>

  407. <td><p><a class="reference internal" href="#collections.abc.MappingView" title="collections.abc.MappingView"><code class="xref py py-class docutils literal notranslate"><span class="pre">MappingView</span></code></a>,

  408. <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate"><span class="pre">Set</span></code></a></p></td>

  409. <td></td>

  410. <td><p><code class="docutils literal notranslate"><span class="pre">__contains__</span></code>,

  411. <code class="docutils literal notranslate"><span class="pre">__iter__</span></code></p></td>

  412. </tr>

  413. <tr class="row-even"><td><p><a class="reference internal" href="#collections.abc.KeysView" title="collections.abc.KeysView"><code class="xref py py-class docutils literal notranslate"><span class="pre">KeysView</span></code></a></p></td>

  414. <td><p><a class="reference internal" href="#collections.abc.MappingView" title="collections.abc.MappingView"><code class="xref py py-class docutils literal notranslate"><span class="pre">MappingView</span></code></a>,

  415. <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate"><span class="pre">Set</span></code></a></p></td>

  416. <td></td>

  417. <td><p><code class="docutils literal notranslate"><span class="pre">__contains__</span></code>,

  418. <code class="docutils literal notranslate"><span class="pre">__iter__</span></code></p></td>

  419. </tr>

  420. <tr class="row-odd"><td><p><a class="reference internal" href="#collections.abc.ValuesView" title="collections.abc.ValuesView"><code class="xref py py-class docutils literal notranslate"><span class="pre">ValuesView</span></code></a></p></td>

  421. <td><p><a class="reference internal" href="#collections.abc.MappingView" title="collections.abc.MappingView"><code class="xref py py-class docutils literal notranslate"><span class="pre">MappingView</span></code></a>,

  422. <a class="reference internal" href="#collections.abc.Collection" title="collections.abc.Collection"><code class="xref py py-class docutils literal notranslate"><span class="pre">Collection</span></code></a></p></td>

  423. <td></td>

  424. <td><p><code class="docutils literal notranslate"><span class="pre">__contains__</span></code>, <code class="docutils literal notranslate"><span class="pre">__iter__</span></code></p></td>

  425. </tr>

  426. <tr class="row-even"><td><p><a class="reference internal" href="#collections.abc.Awaitable" title="collections.abc.Awaitable"><code class="xref py py-class docutils literal notranslate"><span class="pre">Awaitable</span></code></a> <a class="footnote-reference brackets" href="#id18" id="id12" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  427. <td></td>

  428. <td><p><code class="docutils literal notranslate"><span class="pre">__await__</span></code></p></td>

  429. <td></td>

  430. </tr>

  431. <tr class="row-odd"><td><p><a class="reference internal" href="#collections.abc.Coroutine" title="collections.abc.Coroutine"><code class="xref py py-class docutils literal notranslate"><span class="pre">Coroutine</span></code></a> <a class="footnote-reference brackets" href="#id18" id="id13" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  432. <td><p><a class="reference internal" href="#collections.abc.Awaitable" title="collections.abc.Awaitable"><code class="xref py py-class docutils literal notranslate"><span class="pre">Awaitable</span></code></a></p></td>

  433. <td><p><code class="docutils literal notranslate"><span class="pre">send</span></code>, <code class="docutils literal notranslate"><span class="pre">throw</span></code></p></td>

  434. <td><p><code class="docutils literal notranslate"><span class="pre">close</span></code></p></td>

  435. </tr>

  436. <tr class="row-even"><td><p><a class="reference internal" href="#collections.abc.AsyncIterable" title="collections.abc.AsyncIterable"><code class="xref py py-class docutils literal notranslate"><span class="pre">AsyncIterable</span></code></a> <a class="footnote-reference brackets" href="#id18" id="id14" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  437. <td></td>

  438. <td><p><code class="docutils literal notranslate"><span class="pre">__aiter__</span></code></p></td>

  439. <td></td>

  440. </tr>

  441. <tr class="row-odd"><td><p><a class="reference internal" href="#collections.abc.AsyncIterator" title="collections.abc.AsyncIterator"><code class="xref py py-class docutils literal notranslate"><span class="pre">AsyncIterator</span></code></a> <a class="footnote-reference brackets" href="#id18" id="id15" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  442. <td><p><a class="reference internal" href="#collections.abc.AsyncIterable" title="collections.abc.AsyncIterable"><code class="xref py py-class docutils literal notranslate"><span class="pre">AsyncIterable</span></code></a></p></td>

  443. <td><p><code class="docutils literal notranslate"><span class="pre">__anext__</span></code></p></td>

  444. <td><p><code class="docutils literal notranslate"><span class="pre">__aiter__</span></code></p></td>

  445. </tr>

  446. <tr class="row-even"><td><p><a class="reference internal" href="#collections.abc.AsyncGenerator" title="collections.abc.AsyncGenerator"><code class="xref py py-class docutils literal notranslate"><span class="pre">AsyncGenerator</span></code></a> <a class="footnote-reference brackets" href="#id18" id="id16" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  447. <td><p><a class="reference internal" href="#collections.abc.AsyncIterator" title="collections.abc.AsyncIterator"><code class="xref py py-class docutils literal notranslate"><span class="pre">AsyncIterator</span></code></a></p></td>

  448. <td><p><code class="docutils literal notranslate"><span class="pre">asend</span></code>, <code class="docutils literal notranslate"><span class="pre">athrow</span></code></p></td>

  449. <td><p><code class="docutils literal notranslate"><span class="pre">aclose</span></code>, <code class="docutils literal notranslate"><span class="pre">__aiter__</span></code>, <code class="docutils literal notranslate"><span class="pre">__anext__</span></code></p></td>

  450. </tr>

  451. <tr class="row-odd"><td><p><a class="reference internal" href="#collections.abc.Buffer" title="collections.abc.Buffer"><code class="xref py py-class docutils literal notranslate"><span class="pre">Buffer</span></code></a> <a class="footnote-reference brackets" href="#id18" id="id17" role="doc-noteref"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></a></p></td>

  452. <td></td>

  453. <td><p><code class="docutils literal notranslate"><span class="pre">__buffer__</span></code></p></td>

  454. <td></td>

  455. </tr>

  456. </tbody>

  457. </table>

  458. <p class="rubric">Footnotes</p>

  459. <aside class="footnote-list brackets">

  460. <aside class="footnote brackets" id="id18" role="doc-footnote">

  461. <span class="label"><span class="fn-bracket">[</span>1<span class="fn-bracket">]</span></span>

  462. <span class="backrefs">(<a role="doc-backlink" href="#id2">1</a>,<a role="doc-backlink" href="#id3">2</a>,<a role="doc-backlink" href="#id4">3</a>,<a role="doc-backlink" href="#id6">4</a>,<a role="doc-backlink" href="#id7">5</a>,<a role="doc-backlink" href="#id8">6</a>,<a role="doc-backlink" href="#id9">7</a>,<a role="doc-backlink" href="#id10">8</a>,<a role="doc-backlink" href="#id11">9</a>,<a role="doc-backlink" href="#id12">10</a>,<a role="doc-backlink" href="#id13">11</a>,<a role="doc-backlink" href="#id14">12</a>,<a role="doc-backlink" href="#id15">13</a>,<a role="doc-backlink" href="#id16">14</a>,<a role="doc-backlink" href="#id17">15</a>)</span>

  463. <p>These ABCs override <a class="reference internal" href="abc.html#abc.ABCMeta.__subclasshook__" title="abc.ABCMeta.__subclasshook__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__subclasshook__()</span></code></a> to support

  464. testing an interface by verifying the required methods are present

  465. and have not been set to <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a>.  This only works for simple

  466. interfaces.  More complex interfaces require registration or direct

  467. subclassing.</p>

  468. </aside>

  469. <aside class="footnote brackets" id="id19" role="doc-footnote">

  470. <span class="label"><span class="fn-bracket">[</span><a role="doc-backlink" href="#id5">2</a><span class="fn-bracket">]</span></span>

  471. <p>Checking <code class="docutils literal notranslate"><span class="pre">isinstance(obj,</span> <span class="pre">Iterable)</span></code> detects classes that are

  472. registered as <a class="reference internal" href="#collections.abc.Iterable" title="collections.abc.Iterable"><code class="xref py py-class docutils literal notranslate"><span class="pre">Iterable</span></code></a> or that have an <a class="reference internal" href="stdtypes.html#container.__iter__" title="container.__iter__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__iter__()</span></code></a>

  473. method, but it does not detect classes that iterate with the

  474. <a class="reference internal" href="../reference/datamodel.html#object.__getitem__" title="object.__getitem__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__getitem__()</span></code></a> method.  The only reliable way to determine

  475. whether an object is <a class="reference internal" href="../glossary.html#term-iterable"><span class="xref std std-term">iterable</span></a> is to call <code class="docutils literal notranslate"><span class="pre">iter(obj)</span></code>.</p>

  476. </aside>

  477. </aside>

  478. </section>

  479. <section id="collections-abstract-base-classes-detailed-descriptions">

  480. <h2>Collections Abstract Base Classes – Detailed Descriptions<a class="headerlink" href="#collections-abstract-base-classes-detailed-descriptions" title="Link to this heading">¶</a></h2>

  481. <dl class="py class">

  482. <dt class="sig sig-object py" id="collections.abc.Container">

  483. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Container</span></span><a class="headerlink" href="#collections.abc.Container" title="Link to this definition">¶</a></dt>

  484. <dd><p>ABC for classes that provide the <a class="reference internal" href="../reference/datamodel.html#object.__contains__" title="object.__contains__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__contains__()</span></code></a> method.</p>

  485. </dd></dl>

  486. 

  487. <dl class="py class">

  488. <dt class="sig sig-object py" id="collections.abc.Hashable">

  489. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Hashable</span></span><a class="headerlink" href="#collections.abc.Hashable" title="Link to this definition">¶</a></dt>

  490. <dd><p>ABC for classes that provide the <a class="reference internal" href="../reference/datamodel.html#object.__hash__" title="object.__hash__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__hash__()</span></code></a> method.</p>

  491. </dd></dl>

  492. 

  493. <dl class="py class">

  494. <dt class="sig sig-object py" id="collections.abc.Sized">

  495. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Sized</span></span><a class="headerlink" href="#collections.abc.Sized" title="Link to this definition">¶</a></dt>

  496. <dd><p>ABC for classes that provide the <a class="reference internal" href="../reference/datamodel.html#object.__len__" title="object.__len__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__len__()</span></code></a> method.</p>

  497. </dd></dl>

  498. 

  499. <dl class="py class">

  500. <dt class="sig sig-object py" id="collections.abc.Callable">

  501. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Callable</span></span><a class="headerlink" href="#collections.abc.Callable" title="Link to this definition">¶</a></dt>

  502. <dd><p>ABC for classes that provide the <a class="reference internal" href="../reference/datamodel.html#object.__call__" title="object.__call__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__call__()</span></code></a> method.</p>

  503. </dd></dl>

  504. 

  505. <dl class="py class">

  506. <dt class="sig sig-object py" id="collections.abc.Iterable">

  507. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Iterable</span></span><a class="headerlink" href="#collections.abc.Iterable" title="Link to this definition">¶</a></dt>

  508. <dd><p>ABC for classes that provide the <a class="reference internal" href="stdtypes.html#container.__iter__" title="container.__iter__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__iter__()</span></code></a> method.</p>

  509. <p>Checking <code class="docutils literal notranslate"><span class="pre">isinstance(obj,</span> <span class="pre">Iterable)</span></code> detects classes that are registered

  510. as <a class="reference internal" href="#collections.abc.Iterable" title="collections.abc.Iterable"><code class="xref py py-class docutils literal notranslate"><span class="pre">Iterable</span></code></a> or that have an <a class="reference internal" href="stdtypes.html#container.__iter__" title="container.__iter__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__iter__()</span></code></a> method,

  511. but it does

  512. not detect classes that iterate with the <a class="reference internal" href="../reference/datamodel.html#object.__getitem__" title="object.__getitem__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__getitem__()</span></code></a> method.

  513. The only reliable way to determine whether an object is <a class="reference internal" href="../glossary.html#term-iterable"><span class="xref std std-term">iterable</span></a>

  514. is to call <code class="docutils literal notranslate"><span class="pre">iter(obj)</span></code>.</p>

  515. </dd></dl>

  516. 

  517. <dl class="py class">

  518. <dt class="sig sig-object py" id="collections.abc.Collection">

  519. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Collection</span></span><a class="headerlink" href="#collections.abc.Collection" title="Link to this definition">¶</a></dt>

  520. <dd><p>ABC for sized iterable container classes.</p>

  521. <div class="versionadded">

  522. <p><span class="versionmodified added">New in version 3.6.</span></p>

  523. </div>

  524. </dd></dl>

  525. 

  526. <dl class="py class">

  527. <dt class="sig sig-object py" id="collections.abc.Iterator">

  528. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Iterator</span></span><a class="headerlink" href="#collections.abc.Iterator" title="Link to this definition">¶</a></dt>

  529. <dd><p>ABC for classes that provide the <a class="reference internal" href="stdtypes.html#iterator.__iter__" title="iterator.__iter__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__iter__()</span></code></a> and

  530. <a class="reference internal" href="stdtypes.html#iterator.__next__" title="iterator.__next__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__next__()</span></code></a> methods.  See also the definition of

  531. <a class="reference internal" href="../glossary.html#term-iterator"><span class="xref std std-term">iterator</span></a>.</p>

  532. </dd></dl>

  533. 

  534. <dl class="py class">

  535. <dt class="sig sig-object py" id="collections.abc.Reversible">

  536. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Reversible</span></span><a class="headerlink" href="#collections.abc.Reversible" title="Link to this definition">¶</a></dt>

  537. <dd><p>ABC for iterable classes that also provide the <a class="reference internal" href="../reference/datamodel.html#object.__reversed__" title="object.__reversed__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__reversed__()</span></code></a>

  538. method.</p>

  539. <div class="versionadded">

  540. <p><span class="versionmodified added">New in version 3.6.</span></p>

  541. </div>

  542. </dd></dl>

  543. 

  544. <dl class="py class">

  545. <dt class="sig sig-object py" id="collections.abc.Generator">

  546. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Generator</span></span><a class="headerlink" href="#collections.abc.Generator" title="Link to this definition">¶</a></dt>

  547. <dd><p>ABC for <a class="reference internal" href="../glossary.html#term-generator"><span class="xref std std-term">generator</span></a> classes that implement the protocol defined in

  548. <span class="target" id="index-1"></span><a class="pep reference external" href="https://peps.python.org/pep-0342/"><strong>PEP 342</strong></a> that extends <a class="reference internal" href="../glossary.html#term-iterator"><span class="xref std std-term">iterators</span></a> with the

  549. <a class="reference internal" href="../reference/expressions.html#generator.send" title="generator.send"><code class="xref py py-meth docutils literal notranslate"><span class="pre">send()</span></code></a>,

  550. <a class="reference internal" href="../reference/expressions.html#generator.throw" title="generator.throw"><code class="xref py py-meth docutils literal notranslate"><span class="pre">throw()</span></code></a> and <a class="reference internal" href="../reference/expressions.html#generator.close" title="generator.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code></a> methods.</p>

  551. <div class="versionadded">

  552. <p><span class="versionmodified added">New in version 3.5.</span></p>

  553. </div>

  554. </dd></dl>

  555. 

  556. <dl class="py class">

  557. <dt class="sig sig-object py" id="collections.abc.Sequence">

  558. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Sequence</span></span><a class="headerlink" href="#collections.abc.Sequence" title="Link to this definition">¶</a></dt>

  559. <dt class="sig sig-object py" id="collections.abc.MutableSequence">

  560. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">MutableSequence</span></span><a class="headerlink" href="#collections.abc.MutableSequence" title="Link to this definition">¶</a></dt>

  561. <dt class="sig sig-object py" id="collections.abc.ByteString">

  562. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">ByteString</span></span><a class="headerlink" href="#collections.abc.ByteString" title="Link to this definition">¶</a></dt>

  563. <dd><p>ABCs for read-only and mutable <a class="reference internal" href="../glossary.html#term-sequence"><span class="xref std std-term">sequences</span></a>.</p>

  564. <p>Implementation note: Some of the mixin methods, such as

  565. <a class="reference internal" href="stdtypes.html#container.__iter__" title="container.__iter__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__iter__()</span></code></a>, <a class="reference internal" href="../reference/datamodel.html#object.__reversed__" title="object.__reversed__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__reversed__()</span></code></a> and <code class="xref py py-meth docutils literal notranslate"><span class="pre">index()</span></code>, make

  566. repeated calls to the underlying <a class="reference internal" href="../reference/datamodel.html#object.__getitem__" title="object.__getitem__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__getitem__()</span></code></a> method.

  567. Consequently, if <a class="reference internal" href="../reference/datamodel.html#object.__getitem__" title="object.__getitem__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__getitem__()</span></code></a> is implemented with constant

  568. access speed, the mixin methods will have linear performance;

  569. however, if the underlying method is linear (as it would be with a

  570. linked list), the mixins will have quadratic performance and will

  571. likely need to be overridden.</p>

  572. <div class="versionchanged">

  573. <p><span class="versionmodified changed">Changed in version 3.5: </span>The index() method added support for <em>stop</em> and <em>start</em>

  574. arguments.</p>

  575. </div>

  576. <div class="deprecated-removed">

  577. <p><span class="versionmodified">Deprecated since version 3.12, will be removed in version 3.14: </span>The <a class="reference internal" href="#collections.abc.ByteString" title="collections.abc.ByteString"><code class="xref py py-class docutils literal notranslate"><span class="pre">ByteString</span></code></a> ABC has been deprecated.

  578. For use in typing, prefer a union, like <code class="docutils literal notranslate"><span class="pre">bytes</span> <span class="pre">|</span> <span class="pre">bytearray</span></code>, or

  579. <a class="reference internal" href="#collections.abc.Buffer" title="collections.abc.Buffer"><code class="xref py py-class docutils literal notranslate"><span class="pre">collections.abc.Buffer</span></code></a>.

  580. For use as an ABC, prefer <a class="reference internal" href="#collections.abc.Sequence" title="collections.abc.Sequence"><code class="xref py py-class docutils literal notranslate"><span class="pre">Sequence</span></code></a> or <a class="reference internal" href="#collections.abc.Buffer" title="collections.abc.Buffer"><code class="xref py py-class docutils literal notranslate"><span class="pre">collections.abc.Buffer</span></code></a>.</p>

  581. </div>

  582. </dd></dl>

  583. 

  584. <dl class="py class">

  585. <dt class="sig sig-object py" id="collections.abc.Set">

  586. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Set</span></span><a class="headerlink" href="#collections.abc.Set" title="Link to this definition">¶</a></dt>

  587. <dt class="sig sig-object py" id="collections.abc.MutableSet">

  588. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">MutableSet</span></span><a class="headerlink" href="#collections.abc.MutableSet" title="Link to this definition">¶</a></dt>

  589. <dd><p>ABCs for read-only and mutable <a class="reference internal" href="stdtypes.html#types-set"><span class="std std-ref">sets</span></a>.</p>

  590. </dd></dl>

  591. 

  592. <dl class="py class">

  593. <dt class="sig sig-object py" id="collections.abc.Mapping">

  594. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Mapping</span></span><a class="headerlink" href="#collections.abc.Mapping" title="Link to this definition">¶</a></dt>

  595. <dt class="sig sig-object py" id="collections.abc.MutableMapping">

  596. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">MutableMapping</span></span><a class="headerlink" href="#collections.abc.MutableMapping" title="Link to this definition">¶</a></dt>

  597. <dd><p>ABCs for read-only and mutable <a class="reference internal" href="../glossary.html#term-mapping"><span class="xref std std-term">mappings</span></a>.</p>

  598. </dd></dl>

  599. 

  600. <dl class="py class">

  601. <dt class="sig sig-object py" id="collections.abc.MappingView">

  602. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">MappingView</span></span><a class="headerlink" href="#collections.abc.MappingView" title="Link to this definition">¶</a></dt>

  603. <dt class="sig sig-object py" id="collections.abc.ItemsView">

  604. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">ItemsView</span></span><a class="headerlink" href="#collections.abc.ItemsView" title="Link to this definition">¶</a></dt>

  605. <dt class="sig sig-object py" id="collections.abc.KeysView">

  606. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">KeysView</span></span><a class="headerlink" href="#collections.abc.KeysView" title="Link to this definition">¶</a></dt>

  607. <dt class="sig sig-object py" id="collections.abc.ValuesView">

  608. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">ValuesView</span></span><a class="headerlink" href="#collections.abc.ValuesView" title="Link to this definition">¶</a></dt>

  609. <dd><p>ABCs for mapping, items, keys, and values <a class="reference internal" href="../glossary.html#term-dictionary-view"><span class="xref std std-term">views</span></a>.</p>

  610. </dd></dl>

  611. 

  612. <dl class="py class">

  613. <dt class="sig sig-object py" id="collections.abc.Awaitable">

  614. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Awaitable</span></span><a class="headerlink" href="#collections.abc.Awaitable" title="Link to this definition">¶</a></dt>

  615. <dd><p>ABC for <a class="reference internal" href="../glossary.html#term-awaitable"><span class="xref std std-term">awaitable</span></a> objects, which can be used in <a class="reference internal" href="../reference/expressions.html#await"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">await</span></code></a>

  616. expressions.  Custom implementations must provide the

  617. <a class="reference internal" href="../reference/datamodel.html#object.__await__" title="object.__await__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__await__()</span></code></a> method.</p>

  618. <p><a class="reference internal" href="../glossary.html#term-coroutine"><span class="xref std std-term">Coroutine</span></a> objects and instances of the

  619. <a class="reference internal" href="#collections.abc.Coroutine" title="collections.abc.Coroutine"><code class="xref py py-class docutils literal notranslate"><span class="pre">Coroutine</span></code></a> ABC are all instances of this ABC.</p>

  620. <div class="admonition note">

  621. <p class="admonition-title">Note</p>

  622. <p>In CPython, generator-based coroutines (<a class="reference internal" href="../glossary.html#term-generator"><span class="xref std std-term">generators</span></a>

  623. decorated with <a class="reference internal" href="types.html#types.coroutine" title="types.coroutine"><code class="xref py py-func docutils literal notranslate"><span class="pre">&#64;types.coroutine</span></code></a>) are

  624. <em>awaitables</em>, even though they do not have an <a class="reference internal" href="../reference/datamodel.html#object.__await__" title="object.__await__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__await__()</span></code></a> method.

  625. Using <code class="docutils literal notranslate"><span class="pre">isinstance(gencoro,</span> <span class="pre">Awaitable)</span></code> for them will return <code class="docutils literal notranslate"><span class="pre">False</span></code>.

  626. Use <a class="reference internal" href="inspect.html#inspect.isawaitable" title="inspect.isawaitable"><code class="xref py py-func docutils literal notranslate"><span class="pre">inspect.isawaitable()</span></code></a> to detect them.</p>

  627. </div>

  628. <div class="versionadded">

  629. <p><span class="versionmodified added">New in version 3.5.</span></p>

  630. </div>

  631. </dd></dl>

  632. 

  633. <dl class="py class">

  634. <dt class="sig sig-object py" id="collections.abc.Coroutine">

  635. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Coroutine</span></span><a class="headerlink" href="#collections.abc.Coroutine" title="Link to this definition">¶</a></dt>

  636. <dd><p>ABC for <a class="reference internal" href="../glossary.html#term-coroutine"><span class="xref std std-term">coroutine</span></a> compatible classes.  These implement the

  637. following methods, defined in <a class="reference internal" href="../reference/datamodel.html#coroutine-objects"><span class="std std-ref">Coroutine Objects</span></a>:

  638. <a class="reference internal" href="../reference/datamodel.html#coroutine.send" title="coroutine.send"><code class="xref py py-meth docutils literal notranslate"><span class="pre">send()</span></code></a>, <a class="reference internal" href="../reference/datamodel.html#coroutine.throw" title="coroutine.throw"><code class="xref py py-meth docutils literal notranslate"><span class="pre">throw()</span></code></a>, and

  639. <a class="reference internal" href="../reference/datamodel.html#coroutine.close" title="coroutine.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code></a>.  Custom implementations must also implement

  640. <a class="reference internal" href="../reference/datamodel.html#object.__await__" title="object.__await__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__await__()</span></code></a>.  All <a class="reference internal" href="#collections.abc.Coroutine" title="collections.abc.Coroutine"><code class="xref py py-class docutils literal notranslate"><span class="pre">Coroutine</span></code></a> instances are also

  641. instances of <a class="reference internal" href="#collections.abc.Awaitable" title="collections.abc.Awaitable"><code class="xref py py-class docutils literal notranslate"><span class="pre">Awaitable</span></code></a>.</p>

  642. <div class="admonition note">

  643. <p class="admonition-title">Note</p>

  644. <p>In CPython, generator-based coroutines (<a class="reference internal" href="../glossary.html#term-generator"><span class="xref std std-term">generators</span></a>

  645. decorated with <a class="reference internal" href="types.html#types.coroutine" title="types.coroutine"><code class="xref py py-func docutils literal notranslate"><span class="pre">&#64;types.coroutine</span></code></a>) are

  646. <em>awaitables</em>, even though they do not have an <a class="reference internal" href="../reference/datamodel.html#object.__await__" title="object.__await__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__await__()</span></code></a> method.

  647. Using <code class="docutils literal notranslate"><span class="pre">isinstance(gencoro,</span> <span class="pre">Coroutine)</span></code> for them will return <code class="docutils literal notranslate"><span class="pre">False</span></code>.

  648. Use <a class="reference internal" href="inspect.html#inspect.isawaitable" title="inspect.isawaitable"><code class="xref py py-func docutils literal notranslate"><span class="pre">inspect.isawaitable()</span></code></a> to detect them.</p>

  649. </div>

  650. <div class="versionadded">

  651. <p><span class="versionmodified added">New in version 3.5.</span></p>

  652. </div>

  653. </dd></dl>

  654. 

  655. <dl class="py class">

  656. <dt class="sig sig-object py" id="collections.abc.AsyncIterable">

  657. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">AsyncIterable</span></span><a class="headerlink" href="#collections.abc.AsyncIterable" title="Link to this definition">¶</a></dt>

  658. <dd><p>ABC for classes that provide an <code class="docutils literal notranslate"><span class="pre">__aiter__</span></code> method.  See also the

  659. definition of <a class="reference internal" href="../glossary.html#term-asynchronous-iterable"><span class="xref std std-term">asynchronous iterable</span></a>.</p>

  660. <div class="versionadded">

  661. <p><span class="versionmodified added">New in version 3.5.</span></p>

  662. </div>

  663. </dd></dl>

  664. 

  665. <dl class="py class">

  666. <dt class="sig sig-object py" id="collections.abc.AsyncIterator">

  667. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">AsyncIterator</span></span><a class="headerlink" href="#collections.abc.AsyncIterator" title="Link to this definition">¶</a></dt>

  668. <dd><p>ABC for classes that provide <code class="docutils literal notranslate"><span class="pre">__aiter__</span></code> and <code class="docutils literal notranslate"><span class="pre">__anext__</span></code>

  669. methods.  See also the definition of <a class="reference internal" href="../glossary.html#term-asynchronous-iterator"><span class="xref std std-term">asynchronous iterator</span></a>.</p>

  670. <div class="versionadded">

  671. <p><span class="versionmodified added">New in version 3.5.</span></p>

  672. </div>

  673. </dd></dl>

  674. 

  675. <dl class="py class">

  676. <dt class="sig sig-object py" id="collections.abc.AsyncGenerator">

  677. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">AsyncGenerator</span></span><a class="headerlink" href="#collections.abc.AsyncGenerator" title="Link to this definition">¶</a></dt>

  678. <dd><p>ABC for <a class="reference internal" href="../glossary.html#term-asynchronous-generator"><span class="xref std std-term">asynchronous generator</span></a> classes that implement the protocol

  679. defined in <span class="target" id="index-2"></span><a class="pep reference external" href="https://peps.python.org/pep-0525/"><strong>PEP 525</strong></a> and <span class="target" id="index-3"></span><a class="pep reference external" href="https://peps.python.org/pep-0492/"><strong>PEP 492</strong></a>.</p>

  680. <div class="versionadded">

  681. <p><span class="versionmodified added">New in version 3.6.</span></p>

  682. </div>

  683. </dd></dl>

  684. 

  685. <dl class="py class">

  686. <dt class="sig sig-object py" id="collections.abc.Buffer">

  687. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">collections.abc.</span></span><span class="sig-name descname"><span class="pre">Buffer</span></span><a class="headerlink" href="#collections.abc.Buffer" title="Link to this definition">¶</a></dt>

  688. <dd><p>ABC for classes that provide the <a class="reference internal" href="../reference/datamodel.html#object.__buffer__" title="object.__buffer__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__buffer__()</span></code></a> method,

  689. implementing the <a class="reference internal" href="../c-api/buffer.html#bufferobjects"><span class="std std-ref">buffer protocol</span></a>. See <span class="target" id="index-4"></span><a class="pep reference external" href="https://peps.python.org/pep-0688/"><strong>PEP 688</strong></a>.</p>

  690. <div class="versionadded">

  691. <p><span class="versionmodified added">New in version 3.12.</span></p>

  692. </div>

  693. </dd></dl>

  694. 

  695. </section>

  696. <section id="examples-and-recipes">

  697. <h2>Examples and Recipes<a class="headerlink" href="#examples-and-recipes" title="Link to this heading">¶</a></h2>

  698. <p>ABCs allow us to ask classes or instances if they provide

  699. particular functionality, for example:</p>

  700. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">size</span> <span class="o">=</span> <span class="kc">None</span>

  701. <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">myvar</span><span class="p">,</span> <span class="n">collections</span><span class="o">.</span><span class="n">abc</span><span class="o">.</span><span class="n">Sized</span><span class="p">):</span>

  702.     <span class="n">size</span> <span class="o">=</span> <span class="nb">len</span><span class="p">(</span><span class="n">myvar</span><span class="p">)</span>

  703. </pre></div>

  704. </div>

  705. <p>Several of the ABCs are also useful as mixins that make it easier to develop

  706. classes supporting container APIs.  For example, to write a class supporting

  707. the full <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate"><span class="pre">Set</span></code></a> API, it is only necessary to supply the three underlying

  708. abstract methods: <a class="reference internal" href="../reference/datamodel.html#object.__contains__" title="object.__contains__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__contains__()</span></code></a>, <a class="reference internal" href="stdtypes.html#container.__iter__" title="container.__iter__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__iter__()</span></code></a>, and

  709. <a class="reference internal" href="../reference/datamodel.html#object.__len__" title="object.__len__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__len__()</span></code></a>. The ABC supplies the remaining methods such as

  710. <code class="xref py py-meth docutils literal notranslate"><span class="pre">__and__()</span></code> and <a class="reference internal" href="stdtypes.html#frozenset.isdisjoint" title="frozenset.isdisjoint"><code class="xref py py-meth docutils literal notranslate"><span class="pre">isdisjoint()</span></code></a>:</p>

  711. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">ListBasedSet</span><span class="p">(</span><span class="n">collections</span><span class="o">.</span><span class="n">abc</span><span class="o">.</span><span class="n">Set</span><span class="p">):</span>

  712. <span class="w">    </span><span class="sd">&#39;&#39;&#39; Alternate set implementation favoring space over speed</span>

  713. <span class="sd">        and not requiring the set elements to be hashable. &#39;&#39;&#39;</span>

  714.     <span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">iterable</span><span class="p">):</span>

  715.         <span class="bp">self</span><span class="o">.</span><span class="n">elements</span> <span class="o">=</span> <span class="n">lst</span> <span class="o">=</span> <span class="p">[]</span>

  716.         <span class="k">for</span> <span class="n">value</span> <span class="ow">in</span> <span class="n">iterable</span><span class="p">:</span>

  717.             <span class="k">if</span> <span class="n">value</span> <span class="ow">not</span> <span class="ow">in</span> <span class="n">lst</span><span class="p">:</span>

  718.                 <span class="n">lst</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">value</span><span class="p">)</span>

  719. 

  720.     <span class="k">def</span> <span class="fm">__iter__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>

  721.         <span class="k">return</span> <span class="nb">iter</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">elements</span><span class="p">)</span>

  722. 

  723.     <span class="k">def</span> <span class="fm">__contains__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">value</span><span class="p">):</span>

  724.         <span class="k">return</span> <span class="n">value</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">elements</span>

  725. 

  726.     <span class="k">def</span> <span class="fm">__len__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>

  727.         <span class="k">return</span> <span class="nb">len</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">elements</span><span class="p">)</span>

  728. 

  729. <span class="n">s1</span> <span class="o">=</span> <span class="n">ListBasedSet</span><span class="p">(</span><span class="s1">&#39;abcdef&#39;</span><span class="p">)</span>

  730. <span class="n">s2</span> <span class="o">=</span> <span class="n">ListBasedSet</span><span class="p">(</span><span class="s1">&#39;defghi&#39;</span><span class="p">)</span>

  731. <span class="n">overlap</span> <span class="o">=</span> <span class="n">s1</span> <span class="o">&amp;</span> <span class="n">s2</span>            <span class="c1"># The __and__() method is supported automatically</span>

  732. </pre></div>

  733. </div>

  734. <p>Notes on using <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate"><span class="pre">Set</span></code></a> and <a class="reference internal" href="#collections.abc.MutableSet" title="collections.abc.MutableSet"><code class="xref py py-class docutils literal notranslate"><span class="pre">MutableSet</span></code></a> as a mixin:</p>

  735. <ol class="arabic simple">

  736. <li><p>Since some set operations create new sets, the default mixin methods need

  737. a way to create new instances from an <a class="reference internal" href="../glossary.html#term-iterable"><span class="xref std std-term">iterable</span></a>. The class constructor is

  738. assumed to have a signature in the form <code class="docutils literal notranslate"><span class="pre">ClassName(iterable)</span></code>.

  739. That assumption is factored-out to an internal <a class="reference internal" href="functions.html#classmethod" title="classmethod"><code class="xref py py-class docutils literal notranslate"><span class="pre">classmethod</span></code></a> called

  740. <code class="xref py py-meth docutils literal notranslate"><span class="pre">_from_iterable()</span></code> which calls <code class="docutils literal notranslate"><span class="pre">cls(iterable)</span></code> to produce a new set.

  741. If the <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate"><span class="pre">Set</span></code></a> mixin is being used in a class with a different

  742. constructor signature, you will need to override <code class="xref py py-meth docutils literal notranslate"><span class="pre">_from_iterable()</span></code>

  743. with a classmethod or regular method that can construct new instances from

  744. an iterable argument.</p></li>

  745. <li><p>To override the comparisons (presumably for speed, as the

  746. semantics are fixed), redefine <a class="reference internal" href="../reference/datamodel.html#object.__le__" title="object.__le__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__le__()</span></code></a> and

  747. <a class="reference internal" href="../reference/datamodel.html#object.__ge__" title="object.__ge__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__ge__()</span></code></a>,

  748. then the other operations will automatically follow suit.</p></li>

  749. <li><p>The <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate"><span class="pre">Set</span></code></a> mixin provides a <code class="xref py py-meth docutils literal notranslate"><span class="pre">_hash()</span></code> method to compute a hash value

  750. for the set; however, <a class="reference internal" href="../reference/datamodel.html#object.__hash__" title="object.__hash__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__hash__()</span></code></a> is not defined because not all sets

  751. are <a class="reference internal" href="../glossary.html#term-hashable"><span class="xref std std-term">hashable</span></a> or immutable.  To add set hashability using mixins,

  752. inherit from both <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Set()</span></code></a> and <a class="reference internal" href="#collections.abc.Hashable" title="collections.abc.Hashable"><code class="xref py py-meth docutils literal notranslate"><span class="pre">Hashable()</span></code></a>, then define

  753. <code class="docutils literal notranslate"><span class="pre">__hash__</span> <span class="pre">=</span> <span class="pre">Set._hash</span></code>.</p></li>

  754. </ol>

  755. <div class="admonition seealso">

  756. <p class="admonition-title">See also</p>

  757. <ul class="simple">

  758. <li><p><a class="reference external" href="https://code.activestate.com/recipes/576694/">OrderedSet recipe</a> for an

  759. example built on <a class="reference internal" href="#collections.abc.MutableSet" title="collections.abc.MutableSet"><code class="xref py py-class docutils literal notranslate"><span class="pre">MutableSet</span></code></a>.</p></li>

  760. <li><p>For more about ABCs, see the <a class="reference internal" href="abc.html#module-abc" title="abc: Abstract base classes according to :pep:`3119`."><code class="xref py py-mod docutils literal notranslate"><span class="pre">abc</span></code></a> module and <span class="target" id="index-5"></span><a class="pep reference external" href="https://peps.python.org/pep-3119/"><strong>PEP 3119</strong></a>.</p></li>

  761. </ul>

  762. </div>

  763. </section>

  764. </section>

  765. 

  766. 

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  773.   <div>

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  775.     <ul>

  776. <li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">collections.abc</span></code> — Abstract Base Classes for Containers</a><ul>

  777. <li><a class="reference internal" href="#collections-abstract-base-classes">Collections Abstract Base Classes</a></li>

  778. <li><a class="reference internal" href="#collections-abstract-base-classes-detailed-descriptions">Collections Abstract Base Classes – Detailed Descriptions</a></li>

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  780. </ul>

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