code: def _ensure_valid_index(self, value):
          
          # GH5632, make sure that we are a Series convertible
          if not len(self.index) and is_list_like(value):
              try:
                  value = Series(value)
              except (ValueError, NotImplementedError, TypeError):
                  raise ValueError('Cannot set a frame with no defined index '
                                   'and a value that cannot be converted to a '
                                   'Series')
  
              self._data = self._data.reindex_axis(value.index.copy(), axis=1,
                                                   fill_value=np.nan)
docs: Ensure that if we don't have an index, that we can create one from the
          passed value.