@Nullable Object[] result = new @Nullable Object[contents.length];
    System.arraycopy(contents, 0, result, 0, contents.length);
    return result;
  }

  /*
   * a "type A" unmodifiable collection freaks out proactively, even if there
   * wasn't going to be any actual work to do anyway
   */

  @Override
  public boolean addAll(Collection<? extends E> elementsToAdd) {
    throw up();
  }

  @Override

    @Nullable Object[] result = new @Nullable Object[contents.length];
    System.arraycopy(contents, 0, result, 0, contents.length);
    return result;
  }

  /*
   * a "type A" unmodifiable collection freaks out proactively, even if there
   * wasn't going to be any actual work to do anyway
   */

  @Override
  public boolean addAll(Collection<? extends E> elementsToAdd) {
    throw up();
  }

  @Override