*** Collection ＜__NSArrayM: 0x286a79ef0＞ was mutated while being enumerated.

错误信息：
“*** Collection <__NSArrayM: 0x286a79ef0> was mutated while being enumerated.”
错误描述：
一边便利数组，又同时修改这个数组里面的内容，导致崩溃。