* assume that using setCount() to increase the count is permitted iff add()
   * is permitted and similarly for decrease/remove(). We assume that a
   * setCount() no-op is permitted if either add() or remove() is permitted,
   * though we also allow it to "succeed" if neither is permitted.
   */

  private void assertSetCount(E element, int count) {

   * assume that using setCount() to increase the count is permitted iff add()
   * is permitted and similarly for decrease/remove(). We assume that a
   * setCount() no-op is permitted if either add() or remove() is permitted,
   * though we also allow it to "succeed" if neither is permitted.
   */

  private void assertSetCount(E element, int count) {