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Programming FAQ: Mention object.__setattr__ as a technique for delegation (#124617)

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This is used for example by threading.local in the stdlib.
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@ -1613,9 +1613,16 @@ method too, and it must do so carefully. The basic implementation of
self.__dict__[name] = value
...
Most :meth:`!__setattr__` implementations must modify
:attr:`self.__dict__ <object.__dict__>` to store
local state for self without causing an infinite recursion.
Many :meth:`~object.__setattr__` implementations call :meth:`!object.__setattr__` to set
an attribute on self without causing infinite recursion::
class X:
def __setattr__(self, name, value):
# Custom logic here...
object.__setattr__(self, name, value)
Alternatively, it is possible to set attributes by inserting
entries into :attr:`self.__dict__ <object.__dict__>` directly.
How do I call a method defined in a base class from a derived class that extends it?