def validate(cls, policy):
        """Validate subscription policy value."""
        return policy in [cls.OPEN, cls.APPROVAL, cls.CLOSED]
def validate(cls, policy):
        """Validate subscription policy value."""
        return policy in [cls.OPEN, cls.APPROVAL, cls.CLOSED]
def validate ( cls , policy ) : return policy in [ cls . OPEN , cls . APPROVAL , cls . CLOSED ]
Validate subscription policy value.
Validate subscription policy value .