Get the name of the python 3.x method that was called inside of __call__

I'm trying to add a method to a class whenever it is called. For instance:

class X(callable):
    def __init__(self):
        pass

    def __call__(self, *args, **kwargs):
        method_called = self.get_method_name()

        if method_called not in self.__dict__:
            self.__dict__[method_called] = self.generic_function

        super().__call__(self, *args, **kwargs)

    def generic_function(self):
        print("I'm So Generic")

    def a(self):
        print('a')

    def get_method_name(self):
        #get the name of the method trying to be called
        method_name = ?????
        return method_name

def main():
    x = X()
    #should create a method nonexistant_method that acts like generic_function
    x.nonexistant_method()

main()

I realize that this might be an odd thing to want to do, but it's part of a tool that I'm building for some research. Is this possible? Or perhaps there is a better place to accomplish this than in __call__?

Thanks!