def clean(self):
        if ['trigger', 'acknowledge', 'resolve'] not in self.event_type:
            raise ValidationError("'%s' is an invalid event type, valid values are 'trigger', 'acknowledge' and 'resolve'" % self.event_type)
dataset/ETHPy150Open ustream/openduty/openduty/models.py/Incident.clean/swapped operands of `not in`