Not all objects can be weakly referenced; those objects which can include class
instances, functions written in Python (but not in C), instance methods, sets,
-frozensets, some :term:`file objects <file object>`, :term:`generator`\s, type
-objects, sockets, arrays, deques, regular expression pattern objects, and code
+frozensets, some :term:`file objects <file object>`, :term:`generators <generator>`,
+type objects, sockets, arrays, deques, regular expression pattern objects, and code
objects.
.. versionchanged:: 3.2
obj = Dict(red=1, green=2, blue=3) # this object is weak referenceable
-Other built-in types such as :class:`tuple` and :class:`int` do not support weak
-references even when subclassed (This is an implementation detail and may be
-different across various Python implementations.).
+.. impl-detail::
+
+ Other built-in types such as :class:`tuple` and :class:`int` do not support weak
+ references even when subclassed.
Extension types can easily be made to support weak references; see
:ref:`weakref-support`.