Method dedent

Lib/optparse.py:236–239

(self)

        self.level += 1

    def dedent(self):
        self.current_indent -= self.indent_increment
        assert self.current_indent >= 0, "Indent decreased below 0."
        self.level -= 1

    def format_usage(self, usage):
        raise NotImplementedError("subclasses must implement")