How to know iterator tag

Question

Hi

Refer code below:

I just want to call different function for forward_list and vector.

For this, how to find the iterator tag from iterator ?

I know I could have display method taking either vector or forward list as an argument. But just curious to get it work with tag.
https://sololearn.com/compiler-playground/c61gH2GJBiN9/?ref=app