Duck typing and class methods (or, how to use a method from both a class and an instance?)

Question

I have some code which I would like to pass instances or classes interchangeably. All I will do in that code is to call a method that I expect both classes and instances to

Answer 1

You could create an own method type with a specially crafted __get__() method.

In this method, you could do something like this:

class combimethod(object):
    def __init__(self, func):
        self._func = func
    def classmethod(self, func):
        self._classfunc = classmethod(func)
        return self
    def __get__(self, instance, owner):
        if instance is None:
            return self._classfunc.__get__(instance, owner)
        else:
            return self._func.__get__(instance, owner)

class A(object):
    @combimethod
    def go(self):
        print "instance", self
    @go.classmethod
    def go(cls):
        print "class", cls

a=A()
print "i:",
a.go()
print "c:",
A.go()

NOTE: The above is not very thoroughly tested, but seems to work. Nevertheless, it should be seen as a kind of "solution-near pseudo-code", not as a solution. It should give you an idea how to achieve your goal.