docs: def index(self, value, start=None, stop=None):
          """
          L.index(value, [start, [stop]]) -> integer -- return first index of value.
          Raises ValueError if the value is not present.
          """
          if start is None:
              start = 0
          if stop is None:
              stop = len(self._col_list)
          return self._col_list.index(value, start, stop)