message: leave a TODO
diff: @@ -136,6 +136,7 @@ def selfplay(
  pwcs, pis, results = p.to_dataset()
  if idx == 0:
  ds = DataSetV2.from_positions_w_context(pwcs, pis, results)
  + #TODO: this does a lot of needless copying (O(n^2))... fix eventually
  ds.extend(DataSetV2.from_positions_w_context(pwcs, pis, results))
  fname ="{:d}-{:d}".format(int(time.time()), idx)
  with open(os.path.join(output_sgf, fname + '.sgf'), 'w') as f:
  