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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 execute_deferred_effects(self, pos):
 """ Evaluates deferred effects that are triggered by the prefix of the pos on the current beliefstate. For instance, if the effect is triggered by the 'NN' pos, then the effect will be triggered by 'NN' or 'NNS'."""

        costs = 0
        to_delete = []
        for entry in self.__dict__['deferred_effects']:
            effect_pos, effect = entry
            if pos.startswith(effect_pos):
                costs += effect(self)
                to_delete.append(entry)
        # we delete afterwards, because Python cannot delete from a list that
        # is being iterated over without screwing up the iteration.
        for entry in to_delete:
            self.__dict__['deferred_effects'].remove(entry)
        return costs