How did the code worked?

Question

def is_even(x):
if x == 0:
return True
else:
return is_odd(x-1)

def is_odd(x):
return not is_even(x)

print(is_odd(17))
print(is_even(23))

Output:
True
False

Answer 1

This is how it works for 1 and 2 number,

def is_even(x):
if x == 0:
return True
else:
return is_odd(x-1)

def is_odd(x):
return not is_even(x)

print(is_odd(1))
print(is_even(2))

__________________________________

#is_odd(1)
#return not is_even(1) //1
#is_even(1)
#return is_odd(1-1) //0
#is_odd(0)
#return not is_even(0) //0
#is_even(0)
#return True //1

#is_even(2)
#return is_odd(2-1) //1
#is_odd(1)
#return not is_even(1) //1
#is_even(1)
#return is_odd(1-1) //0
#is_odd(0)
#return not is_even(0) //0
#is_even(0)
#return True //1

return returns back the value to first call in both examples . Those values after "//" are the values returned by it from the bottom