C ++ 11：函数模板返回任意类型的2D容器

I'm trying to solve a college problem, that, among other things, requires us to write a function which takes a parameter: container of Type1, that contains containers of Type2, which contain containers of Type3, which contain elements of an arbitrary type. The container types do not have to be different, but all that is known is that they support only a few functions (e.g. size( )), and that all the dimensions are the same. We've only dealt with sequence containers so far, so I presume they'll be testing this with custom sequence containers.I'm trying to solve a college problem, that, am