Booleans have two possible values. Are there types that have three possible values? [duplicate]

Answer 1

This is called Ternary logic or Three-valued Logic. As other answers suggest, you could either implement a class:

class Ternary:
    FALSE = 0
    TRUE = 1
    UNKNOWN = 2

Myself, I would probably go for your solution (True, False, None) but I understand your concern.