@NotNull
  private CommittedChangeList zip(@NotNull RepositoryLocationGroup group, @NotNull List<? extends CommittedChangeList> equalLists) {
    if (equalLists.isEmpty()) {
      throw new IllegalArgumentException("equalLists can not be empty");
    }

    return equalLists.size() > 1 ? myVcsPartner.zip(group, equalLists) : equalLists.get(0);
  }
@NotNull
  private CommittedChangeList zip(@NotNull RepositoryLocationGroup group, @NotNull List<? extends CommittedChangeList> equalLists)