code: def index(self, value):
          '''S.index(value) -> integer -- return first index of value.
             Raises ValueError if the value is not present.
          '''
          for i, v in enumerate(self):
              if v == value:
                  return i
          raise ValueErrof index(self, value):
          '''S.index(value) -> integer -- return first index of value.
             Raises ValueError if the value is not present.
          '''
          for i, v in enumerate(self):
              if v == value:
                  return i
          raise ValueError
docs: S.index(value) -> integer -- return first index of value.
             Raises ValueError if the value is not present.