@Contract(pure=true)
  public static <T> int indexOfIdentity(T @NotNull [] array, T element) {
    for (int i = 0; i < array.length; i++) {
      if (array[i] == element) {
        return i;
      }
    }
    return -1;
  }
@Contract(pure=true)
  public static <T> int indexOfIdentity(T @NotNull [] array, T element)