What are your best examples on functions within functions programing.

Question

My strength programming language would be Python, Some Java, Can't go wrong with web development.
With examples would you use password verification, without decorators or loops.

IF
someone has already asked this question. print Sorry
Else
print nevermind me and proceed with your examples
:p

Answer 1

I had this task for internship to make a simple card game using functional programming. It's a bit too complicated to explain in detail, but there was this function to make a list of pairs from two lists. Because the lists needed to be equal, it also accepts supplier functions. If input lists were not equal, the function would call supplier functions to fill up smaller list with objects user wanted.
I didn't get internship because I used Java.

Answer 2

No idea, probably F# or something.

Answer 3

So which language they expected from you?