'Return a list of users with the specified role/course pair'

def get_queryset(self):

    name = self.kwargs['name']
    course_id_string = self.request.query_params.get('course_id')
    if (not course_id_string):
        raise ParseError('course_id    must    be    specified')
    course_id = SlashSeparatedCourseKey.from_deprecated_string(course_id_string)
    role = Role.objects.get_or_create(course_id=course_id, name=name)[0]
    users = role.users.prefetch_related('preferences').select_related('profile').all()
    return users
