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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 trash_for(self, user):
 """ Returns all messages that were either received or sent by the given user and are marked as deleted. """

        return self.filter(
            recipient=user,
            recipient_deleted_at__isnull=False,
        ) | self.filter(
            sender=user,
            sender_deleted_at__isnull=False,
        )