Make it clear that setting __class__ on a module has worked since 3.5,
but support for __getattr__ and __dir__ on module instances requires 3.7+
Patch by Cheryl Sabella.
the module globals (whether by code within the module, or via a reference
to the module's globals dictionary) is unaffected.
+.. versionchanged:: 3.5
+ ``__class__`` module attribute is now writable.
+
+.. versionadded:: 3.7
+ ``__getattr__`` and ``__dir__`` module attributes.
+
+.. seealso::
+
+ :pep:`562` - Module __getattr__ and __dir__
+ Describes the ``__getattr__`` and ``__dir__`` functions on modules.
+
.. _descriptors: