Return a function from a signature
        Args:
            function_signature (str): signature of the function (without return statement)
        Returns:
            Function

def get_function_from_signature(self, function_signature):
        """
            Return a function from a signature
        Args:
            function_signature (str): signature of the function (without return statement)
        Returns:
            Function
        """
        return next((f for f in self.functions if f.full_name == function_signature), None)