Given that functions are objects in Python, you can "register" both the instance and its method in one operation:

>>> class Thing(object):
... \tdef aMethod(self, aParam):
... \t\tself.Value = aParam * 3
... \t\t
>>> some = Thing()
>>> some.aMethod
<bound method Thing.aMethod of <__main__.Thing object at 0x0128CE90>>
>>> f = some.aMethod
>>> f(4)
>>> print some.Value
12

In this example, f gets bound to the method for the "some" instance.