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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 count_unread_messages_between(self, um_to_user, um_from_user):
 """ Returns the amount of unread messages between two users :param um_to_user: A Django :class:`User` for who the messages are for. :param um_from_user: A Django :class:`User` from whom the messages originate from. :return: An integer with the amount of unread messages. """

        unread_total = self.filter(message__sender=um_from_user,
                                   user=um_to_user,
                                   read_at__isnull=True,
                                   deleted_at__isnull=True).count()

        return unread_total