'Return a django QuerySet for all of the users with this role'

def users_with_role(self):

    if (self.course_key is None):
        self.course_key = CourseKeyField.Empty
    entries = User.objects.filter(courseaccessrole__role=self._role_name, courseaccessrole__org=self.org, courseaccessrole__course_id=self.course_key)
    return entries
