code: public final void removeAreaListener(@NonNull final AreaListener listener) {
          Condition.INSTANCE.ensureNotNull(listener, "The listener may not be null");
          this.areaListeners.remove(listener);
      }
docs: Removes a specific listener, which should not be notified, when an area is modified by the
  decorator, anymore.
  
  @param listener
  The listener, which should be added, as an instance of the type {@link AreaListener}.
  The listener may not be null