code: @SuppressWarnings("unchecked")
  	public void close() throws IOException {
  		if(itr instanceof CloseableIterator) {
  			CloseableIterator<E> toBeClosed = (CloseableIterator<E>) itr;
  			toBeClosed.close();
  		}
  	}
docs: /* (non-Javadoc)
  @see org.archive.wayback.util.Cleanable#clean()