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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def apmAggregate(self, **criteria):
 """collect all match history's apm data to report player's calculated MMR"""

        apms = [m.apm(self) for m in self.matchSubset(**criteria)]
        if not apms: return 0 # no apm information without match history
        return sum(apms) / len(apms)