code: def _find_row_label_positions(self, match_value_or_fct, levels=None):
          
          allmatches = find_locations(self.df.index, match_value_or_fct, levels)
          if allmatches and self.inc_index:  # tramslate back
              allmatches = [m + self.nhdrs for m in allmatches]
          return allmatches
docs: Check the original DataFrame's row labels to find the locations of rows. And return the adjusted
          row indexing within region (offset if including index)