Problem in function.

Question

Can you explain this code with another easy example?
I dont uderstand it.

https://code.sololearn.com/cyWQLJwenH4O/?ref=app

Answer 1

in do_twice you pass the add function, so what happens is this:

add(add(5, 10), add(5, 10))
which is
add(15, 15)

Answer 2

If you are using return you have to use if statement before return.