Very simple demonstration of the logic behind the "Two Guardians" riddle from The Labyrinth, the bool argument is the [unknown] true state of the door in question. Because the nature of each guardian is applied to the answer, we are guaranteed exactly one logical "not" and therefore should accept the opposite of our answer as the truth.

doorRiddle.py

def liar(answer):
 return !answer
 
def honest(answer):
 return answer
 
#"Would that door say that this is the door to the castle?"
#if asking the liar, and the liar is the death door:
print(liar(honest(false)))   # "True"

#if asking the liar, and the liar is the castle door:
print(liar(honest(true)))    # "False"

#if asking the honest door, and the honest door is the death door:
print(honest(liar(false)))   # "True"

#if asking the honest door, and the honest door is the castle door:
print(honest(liar(true)))    # "False"