Methods are type specialized functions, just syntactic sugar for calling functions with a context (provided by an instance of the required type) that you defined elsewhere.

    class Foo(object):
        def __init__(self, bar):
            self.bar = bar
        def something(self, arg):
            return [self.bar, arg]

I can do this:

    assert(Foo('spam').something('eggs') == Foo.something(Foo('spam'), 'eggs')

But I could also do this:

   assert(Foo('spam').something(Foo('ham'), 'eggs') == ['ham', 'eggs'])