如果让一个对象集合 list.get(i)取值时 不报错、

我需要取集合的第一个元素，取之前需要先判断这个元素是否存在

文档中说可以用
include(coll, element)

但是我的元素是对象，也不清楚对象具体是什么，也没法用include(list,某个对象)，如何不报错直接返回空

No source files or tests are named. Start by locating the implementation and documentation for list.get(i), then determine the intended out-of-range return behavior for object collections and how it should relate to include(coll, element). Done means the agreed behavior is documented and covered by tests.

Written by the indexing model from the issue text.