@Contract(pure = true)
  public static @Unmodifiable @NotNull <T> List<T> skipNulls(@NotNull Collection<? extends T> collection) {
    return findAll(collection, Conditions.notNull());
  }
@Contract(pure = true)
  public static @Unmodifiable @NotNull <T> List<T> skipNulls(@NotNull Collection<? extends T> collection)