code: def index(self, value):
          
          try:
              diff = value - self._start
          except TypeError:
              raise ValueError('%r is not in range' % value)
          quotient, remainder = divmod(diff, self._step)
          if remainder == 0 and 0 <= quotient < self._len:
              return abs(quotient)
          raise ValueError('%r is not in range' % value)
docs: Return the 0-based position of integer `value` in
          the sequence this range represents.