Why is this code written this way instead of this way?

Question

For this activity:
https://code.sololearn.com/339/#py

I re-wrote it and I believe that it does the same thing, I'm not sure:

def add(x, y):
return x + y

def do_twice(placeholder, x, y):
return ((x + y) + (x + y))

a = 5

b = 10

print(do_twice(add, a, b))

And why does it work with placeholder and not without?

Answer 1

because you pass add as the first parameter of do_twice
Here do_twice should have return :
return placeholder(placeholder(x,y),placeholder(x,y))

Answer 2

thanks bro. it makes sense now, I'm a true beginner, I've never did any programming before. I get this concept now.

Answer 3

You're welcome :)
Do not worry, with practice you will improve fast :)