Get where a specific function is called.
        :param function_address:    Address of the target function
        :return:                    A list of CFGNodes whose exits include a call/jump to the given function

def _get_callsites(self, function_address):
        """
        Get where a specific function is called.
        :param function_address:    Address of the target function
        :return:                    A list of CFGNodes whose exits include a call/jump to the given function
        """

        all_predecessors = []

        nodes = self.get_all_nodes(function_address)
        for n in nodes:
            predecessors = list(self.get_predecessors(n))
            all_predecessors.extend(predecessors)

        return all_predecessors