return this;
    }

    private void add(@Nullable Object[] elements, int n) {
      getReadyToExpandTo(size + n);
      /*
       * The following call is not statically checked, since arraycopy accepts plain Object for its
       * parameters. If it were statically checked, the checker would still be OK with it, since
       * we're copying into a `contents` array whose type allows it to contain nulls. Still, it's

    return (ImmutableList<E>) EMPTY;
  }

  /**
   * Returns an immutable list containing a single element. This list behaves and performs
   * comparably to {@link Collections#singletonList}, but will not accept a null element. It is
   * preferable mainly for consistency and maintainability of your code.
   *
   * @throws NullPointerException if {@code element} is null
   */
  public static <E> ImmutableList<E> of(E element) {