def get_first_param_type(self):
        """
        Return the type annotation of the first argument if it's not empty.
        """
        if not self.sig:
            return None

        params = list(self.sig.parameters.values())
        if params and params[0].annotation is not inspect.Parameter.empty:
            return params[0].annotation

        return None

        Return the type annotation of the first argument if it's not empty.
        
product/gradle-plugin/src/main/python/attr/_compat.py