How can I know the name of "caller"

[billiejoex]

Hi there,
unfortunately, I'm compelled to apply a sort of monkey patching at the
code of an existing libreary that I can't modify directly.
Here's my question
Having such code:

class test:

    def caller(self):
        self.b()

    def called(self):
        pass

...(if it is possible) how can I get, from method "called", the name
of function/method that called it (in this case "caller")?

Thanks in advance