Issue with making object callable in python

Question

I wrote code like this

>>> class a(object):
        def __init__(self):
            self.__call__ = lambda x:x

>>> b = a()

I

Answer 1

__call__ needs to be defined on the class, not the instance

class a(object):
    def __init__(self):
        pass
    __call__ = lambda x:x

but most people probably find it more readable to define the method the usual way

class a(object):
    def __init__(self):
        pass
    def __call__(self):
        return self

If you need to have different behaviour for each instance you could do it like this

class a(object):
    def __init__(self):
        self.myfunc = lambda x:x

    def __call__(self):
        return self.myfunc(self)