private @NotNull ActionGroup createActionGroup(@NotNull GitFileRevision rev,
                                                 @NotNull FilePath filePath,
                                                 @NotNull Collection<? extends GitFileRevision> parents) {
    Collection<AnAction> actions = new ArrayList<>(2);
    for (GitFileRevision parent : parents) {
      actions.add(createParentAction(rev, filePath, parent));
    }
    return new DefaultActionGroup(actions.toArray(AnAction.EMPTY_ARRAY));
  }
private @NotNull ActionGroup createActionGroup(@NotNull GitFileRevision rev,
                                                 @NotNull FilePath filePath,
                                                 @NotNull Collection<? extends GitFileRevision> parents)