code: def moves_from_last_n_games(self, n, moves, shuffle,
                                  column_family, column):
          
          self.wait_for_fresh_games()
          latest_game = self.latest_game_number
          utils.dbg('Latest game in %s: %s' % (self.btspec.table, latest_game))
          if latest_game == 0:
              raise ValueError('Cannot find a latest game in the table')
  
          start = int(max(0, latest_game - n))
          ds = self.moves_from_games(start, latest_game, moves, shuffle,
                                     column_family, column)
          return ds
docs: Randomly choose a given number of moves from the last n games.
  
          Args:
            n:  number of games at the end of this GameQueue to source.
            moves:  number of moves to be sampled from `n` games.
            shuffle:  if True, shuffle the selected moves.
            column_family:  name of the column family containing move examples.
            column:  name of the column containing move examples.
  
          Returns:
            a dataset containing the selected moves.