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),),
                        )