private @Nullable HgCommandResult graft(@NotNull List<String> params) {
    List<String> args = new ArrayList<>();
    args.add("--log");
    args.addAll(params);
    try (AccessToken ignore = DvcsUtil.workingTreeChangeStarted(myProject, HgBundle.message("activity.name.graft"), HgActivity.Graft)) {
      HgCommandResult result =
        new HgCommandExecutor(myProject)
          .executeInCurrentThread(myRepository.getRoot(), "graft", args);
      myRepository.update();
      return result;
    }
  }
private @Nullable HgCommandResult graft(@NotNull List<String> params)