create_aggregate] class WeightedAverage(object): def __init__(self): self.total_weight = 0.0 self.total_ct = 0.0 def step(self, value, wt=None): wt = wt or 1.0 self.total_weight += * value def finalize(self): if self.total_weight != 0.0: return self.total_ct / self.total_weight return 0.0 ext_db.adapter.register_aggregate(WeightedAverage, 2, 'weighted_avg')

total_weight = 0.0 self.total_ct = 0.0 def step(self, value, wt=None): wt = wt or 1.0 self.total_weight += wt self.total_ct += wt * value def finalize(self): if self.total_weight != 0.0: return self self.total_ct / self.total_weight return 0.0 ext_db.adapter.register_aggregate(WeightedAverage, 2, ’weighted_avg’) • custom collations 1.9. Playhouse, a collection of addons 63 peewee Documentation, Release