@classmethod
def get_key_by_ticket(cls, ticket_str):
    try:
        return db.Key(encoded=ticket_str)
    except:
        raise ValueError(('Cannot make _ExternalTask key from ticket value: %s' % ticket_str))
@classmethod
def get_key_by_ticket(cls, ticket_str):
    try:
        return db.Key(encoded=ticket_str)
    except:
        raise ValueError(('Cannot make _ExternalTask key from ticket value: %s' % ticket_str))