def info(self, i):
        """Return source & offset for index `i`."""
        try:
            return self.items[i]
        except IndexError:
            if i == len(self.data):     # Just past the end
                return self.items[1 - i][0], None
            else:
                raise
dataset/ETHPy150Open adieu/allbuttonspressed/docutils/statemachine.py/ViewList.info/swapped operands of `-`