def hapaxes(self):
        return [item for item in self if self[item] == 1]
register an incoming event request with the requesting yard id
dataset/ETHPy150Open nltk/nltk/nltk/probability.py/FreqDist.hapaxes--crossover with--dataset/ETHPy150Open saltstack/salt/salt/daemons/flo/core.py/SaltRaetEventer._register_event_yard