def create_default_groups(self):
        for group in self.groups:
            group = group.replace(" ", "_").lower()
            self[group] = NamedRequirements(group)
def __init__(self, key):
        self.key = key
        self.prio = random.randint(0, 1000000000)
        self.size = 1
        self.left = None
        self.right = None