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Diffstat (limited to 'Doc/library/weakref.rst')
| -rw-r--r-- | Doc/library/weakref.rst | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/Doc/library/weakref.rst b/Doc/library/weakref.rst index 1bf6b58..78ff21d0 100644 --- a/Doc/library/weakref.rst +++ b/Doc/library/weakref.rst @@ -111,6 +111,15 @@ Extension types can easily be made to support weak references; see This is a subclassable type rather than a factory function. + .. attribute:: __callback__ + + This read-only attribute returns the callback currently associated to the + weakref. If there is no callback or if the referent of the weakref is + no longer alive then this attribute will have value ``None``. + + .. versionadded:: 3.4 + Added the :attr:`__callback__` attribute. + .. function:: proxy(object[, callback]) @@ -261,8 +270,9 @@ These method have the same issues as the and :meth:`keyrefs` method of Weak Reference Objects ---------------------- -Weak reference objects have no attributes or methods, but do allow the referent -to be obtained, if it still exists, by calling it: +Weak reference objects have no methods and no attributes besides +:attr:`ref.__callback__`. A weak reference object allows the referent to be +obtained, if it still exists, by calling it: >>> import weakref >>> class Object: |