@SafeVarargs
  @Contract(mutates = "param1")
  public static @NotNull <T, C extends Collection<? super T>> C addAll(@NotNull C collection, T @NotNull ... elements) {
    //noinspection ManualArrayToCollectionCopy
    for (T element : elements) {
      //noinspection UseBulkOperation
      collection.add(element);
    }
    return collection;
  }
@SafeVarargs
  @Contract(mutates = "param1")
  public static @NotNull <T, C extends Collection<? super T>> C addAll(@NotNull C collection, T @NotNull ... elements)