def refactor_string(self, data, name):
        """Refactor a given input string.

        Args:
            data: a string holding the code to be refactored.
            name: a human-readable name for use in error/log messages.

        Returns:
            An AST corresponding to the refactored input stream; None if
            there were errors during the parse.
        """
        features = _detect_future_features(data)
        if "print_function" in features:
            self.driver.grammar = pygram.python_grammar_no_print_statement
        try:
            tree = self.driver.parse_string(data)
        except Exception as err:
            self.log_error("Can't parse %s: %s: %s",
                           name, err.__class__.__name__, err)
            return
        finally:
            self.driver.grammar = self.grammar
        tree.future_features = features
        self.log_debug("Refactoring %s", name)
        self.refactor_tree(tree, name)
        return tree
Refactor a given input string.

        Args:
            data: a string holding the code to be refactored.
            name: a human-readable name for use in error/log messages.

        Returns:
            An AST corresponding to the refactored input stream; None if
            there were errors during the parse.