public boolean insertAt(int index, E element) {
		if (indexOK(index)) {
			if (index == 0) { 
				addFirst(element);
			} else {
				expandArrayCapacityBy(1);
				System.arraycopy(array, index, array, index+1, array.length - index - 1);
				array[index] = element;
			}
			return true;
		}
		return false;
	}