Corresponding to collections in :mod:`collections.abc`
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-.. class:: AbstractSet(Sized, Collection[T_co])
+.. class:: AbstractSet(Collection[T_co])
A generic version of :class:`collections.abc.Set`.
:class:`collections.abc.KeysView` now supports subscripting (``[]``).
See :pep:`585` and :ref:`types-genericalias`.
-.. class:: Mapping(Sized, Collection[KT], Generic[VT_co])
+.. class:: Mapping(Collection[KT], Generic[KT, VT_co])
A generic version of :class:`collections.abc.Mapping`.
This type can be used as follows::