Add clear()

Author: AA-Turner

Doc/reference/datamodel.rst

@@ -3142,16 +3142,20 @@ objects.  The :mod:`collections.abc` module provides a
 :term:`abstract base class` to help create those methods from a base set of
 :meth:`~object.__getitem__`, :meth:`~object.__setitem__`,
 :meth:`~object.__delitem__`, and :meth:`!keys`.
-Mutable sequences should provide methods :meth:`~sequence.append`,
-:meth:`~sequence.count`, :meth:`~sequence.index`, :meth:`~sequence.extend`,
-:meth:`~sequence.insert`, :meth:`~sequence.pop`, :meth:`~sequence.remove`,
-and :meth:`~sequence.reverse`, like Python standard :class:`list` objects.
+
+Mutable sequences should provide methods
+:meth:`~sequence.append`, :meth:`~sequence.clear`, :meth:`~sequence.count`,
+:meth:`~sequence.extend`, :meth:`~sequence.index`, :meth:`~sequence.insert`,
+:meth:`~sequence.pop`, :meth:`~sequence.remove`, and :meth:`~sequence.reverse`,
+like Python standard :class:`list` objects.
 Finally, sequence types should implement addition (meaning concatenation) and
 multiplication (meaning repetition) by defining the methods
 :meth:`~object.__add__`, :meth:`~object.__radd__`, :meth:`~object.__iadd__`,
 :meth:`~object.__mul__`, :meth:`~object.__rmul__` and :meth:`~object.__imul__`
 described below; they should not define other numerical
-operators.  It is recommended that both mappings and sequences implement the
+operators.
+
+It is recommended that both mappings and sequences implement the
 :meth:`~object.__contains__` method to allow efficient use of the ``in``
 operator; for
 mappings, ``in`` should search the mapping's keys; for sequences, it should