def GET_AUTH(self, courseid):  # pylint: disable=arguments-differ
        """ GET request """
        course, __ = self.get_course_and_check_rights(courseid)

        if course.is_lti():
            raise web.notfound()

        if "download" in web.input():
            web.header('Content-Type', 'text/x-yaml', unique=True)
            web.header('Content-Disposition', 'attachment; filename="aggregations.yaml"', unique=True)
            if course.use_classrooms():
                aggregations = [{"default": aggregation["default"],
                               "description": aggregation["description"],
                               "groups": aggregation["groups"],
                               "students": aggregation["students"],
                               "tutors": aggregation["tutors"]} for aggregation in
                              self.user_manager.get_course_aggregations(course)]
            else:
                aggregations = [{"default": aggregation["default"],
                               "description": aggregation["description"],
                               "groups": aggregation["groups"],
                               "students": aggregation["students"],
                               "tutors": aggregation["tutors"]} for aggregation in
                              self.user_manager.get_course_aggregations(course) if len(aggregation["groups"]) > 0]

            return yaml.dump(aggregations)

        return self.page(course)
GET request