code: def _select_model(n2_bounds, n2_result, n3_result, out_dir, data):
      
      n2_out_file = n2_result.replace(".n2.results", ".BEST.results")
      n3_out_file = n3_result.replace(".n3.results", ".BEST.results")
      if not utils.file_exists(n2_out_file) and not utils.file_exists(n3_out_file):
          cmd = _get_cmd("ModelSelection.py") + [n2_bounds, n2_result, n3_result]
          do.run(cmd, "Select best THetA model")
      if utils.file_exists(n2_out_file):
          return n2_out_file
      else:
          assert utils.file_exists(n3_out_file)
          return n3_out_file
docs: Run final model selection from n=2 and n=3 options.