docs: public static <T> void notNullList(List<T> list) {
  		if (isEmpty(list)) {
  			return;
  		}
  
  		Iterator<T> ite = list.iterator();
  		while (ite.hasNext()) {
  			T obj = ite.next();
  			// 清理掉null的集合
  			if (null == obj) {
  				ite.remove();
  			}
  		}
  	}