library/library_member/views/library_menu.xml

<odoo>
    <act_window id="action_library_member"
        name="Library Members"
        res_model="library.member"
        view_mode="tree,form" />

    <menuitem id="menu_library_member"
        action="action_library_member"
        name="member"
        parent="library_app.menu_library" />
</odoo>