Overriding a method in an instance

[Martyn Quick]

I was wondering what the correct way to change the definition of a method
of an instance of a class is.  The following seems to work:

class TestClass:
    def func(self):
        print "1"

def newfunc():
    print "2"

instance = TestClass()
instance.func = newfunc

Whereas, trying to redefine  instance.func  doesn't work.
Is the above the right way to change this method?  [Is there anyway of
doing it without having to introduce "newfunc" as above?]

Martyn

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Dr. Martyn Quick  (Research Fellow in Pure Mathematics)
University of Birmingham, Edgbaston, Birmingham, UK.
http://www.mat.bham.ac.uk/M.R.Quick