Code 1.Please explain this code.

Question

def x(a=0):
def y(b=a):
return a + b
if a == 0:
return y
return y(a)
print(x()(3))

Answer 1

Lets read it from the bottom, print x() so x is a function or def which you can see in the first line , inside of the x we see 'a' as a variable is equal to 0 it means x function shoud have an input otherwise manually puts 0 for a
x(a=0)
return(a)
Print(x() )
#0
Print(x(3))
#3
The same happens to the y function and its inside x function ,it means if x function called go and then call y function and do whatever is inside it(in this case a+b) then check the if statement