def previous_line(self, n=1):
        """Load `self.line` with the `n`'th previous line and return it."""
        self.line_offset -= n
        if 0 < self.line_offset:
            self.line = None
        else:
            self.line = self.input_lines[self.line_offset]
        self.notify_observers()
        return self.line
dataset/ETHPy150Open adieu/allbuttonspressed/docutils/statemachine.py/StateMachine.previous_line/swapped operands of `<`