Func() inside a Func()

Question

#Could you check my explanation

def apply_twice(func, arg):
return func(func(arg))

#for now ignore the above part
#in the def you can write whatever you want

def add_five(x):
return x + 5
#in here you have a function and a variable x
#x=10 from the last line, so add five x would = to 10 + 5 = 15

print(apply_twice(add_five, 10))
#now we have the first function that we ignored.
#the value of x is 15 and then you going to execute the last line, which will be the last value of x which 15 + 5 = 20

Answer 1

Personally, I'd go more along the lines of:
print(apply_twice(add_five, 10))
substituting apply_twice yields:
print(add_five(add_five(10)))
replacing the inner add_five:
print(add_five(10+5))
and the outer:
print(15+5)
finishes with:
print(20)

Your ignore the above part skips how you got to add_five in the first place.

Answer 2

because this part only shows
def apply_twice(func, arg):
return func(func(arg))

that a func must be processed within another func right