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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 create_store(self):
 """ Creates store object """

        if self.store_class is not None:
            return self.store_class.load(self.client.webfinger, self)

        raise NotImplementedError("You need to specify PyPump.store_class or override PyPump.create_store method.")