@Override
	public E pollLast() {
		int size = size();
        if (size == 0) {
            return null;
        }
        return doRemove(size-1);
	}
Helper method for adding multiple elements to the list.
This default implementation calls doAdd() for adding each element.

@param index index where element should be added
             (-1 is valid for adding at the end)
@return      true if elements have been added, false otherwise
jphp-runtime/src/php/runtime/memory/support/IList.java