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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 put_multi(self, entities):
 """Save entities in the Cloud Datastore. :type entities: list of :class:`google.cloud.datastore.entity.Entity` :param entities: The entities to be saved to the datastore. :raises: :class:`ValueError` if ``entities`` is a single entity. """

        if isinstance(entities, Entity):
            raise ValueError("Pass a sequence of entities")

        if not entities:
            return

        current = self.current_batch
        in_batch = current is not None

        if not in_batch:
            current = self.batch()
            current.begin()

        for entity in entities:
            current.put(entity)

        if not in_batch:
            current.commit()