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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 by_classifiers(cls, session, classifiers):
 """ Get releases for given classifiers. :param session: SQLAlchemy session :type session: :class:`sqlalchemy.Session` :param classifiers: classifiers :type classifiers: unicode :return: release instances :rtype: generator of :class:`pyshop.models.Release` """

        return cls.find(session,
                        join=(cls.classifiers,),
                        where=(Classifier.name.in_(classifiers),),
                        )