docs: @Override
  	public final Bitmap remove(String key) {
  		if (key == null) {
  			throw new NullPointerException("key == null");
  		}
  
  		synchronized (this) {
  			Bitmap previous = map.remove(key);
  			if (previous != null) {
  				size -= sizeOf(key, previous);
  			}
  			return previous;
  		}
  	}