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(python2.1-lib.info)Methods

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Methods
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Methods are functions that are called using the attribute notation.
There are two flavors: built-in methods (such as `append()' on lists)
and class instance methods.  Built-in methods are described with the
types that support them.

The implementation adds two special read-only attributes to class
instance methods: `M.im_self' is the object on which the method
operates, and `M.im_func' is the function implementing the method.
Calling `M(ARG-1, ARG-2, ..., ARG-N)' is completely equivalent to
calling `M.im_func(M.im_self, ARG-1, ARG-2, ..., ARG-N)'.

Class instance methods are either _bound_ or _unbound_, referring to
whether the method was accessed through an instance or a class,
respectively.  When a method is unbound, its `im_self' attribute will
be `None' and if called, an explicit `self' object must be passed as
the first argument.  In this case, `self' must be an instance of the
unbound method's class (or a subclass of that class), otherwise a
`TypeError' is raised.

Like function objects, methods objects support getting arbitrary
attributes.  However, since method attributes are actually stored on
the underlying function object (i.e. `meth.im_func'), setting method
attributes on either bound or unbound methods is disallowed.
Attempting to set a method attribute results in a `TypeError' being
raised.  In order to set a method attribute, you need to explicitly set
it on the underlying function object:

     class C:
         def method(self):
             pass
     
     c = C()
     c.method.im_func.whoami = 'my name is c'

See the  for more information.