docs: def bleakest_moves(self, start_game, end_game):
          """Given a range of games, return the bleakest moves.
  
          Returns a list of (game, move, q) sorted by q.
          """
          bleak = b'bleakest_q'
          rows = self.bt_table.read_rows(
              ROW_PREFIX.format(start_game),
              ROW_PREFIX.format(end_game),
              filter_=bigtable_row_filters.ColumnRangeFilter(
                  METADATA, bleak, bleak))
  
          def parse(r):
              rk = str(r.row_key, 'utf-8')
              g, m = _game_row_key.match(rk).groups()
              q = r.cell_value(METADATA, bleak)
              return int(g), int(m), float(q)
          return sorted([parse(r) for r in rows], key=operator.itemgetter(2))