code: def user_courses(self):
          '''
              Returns the list of courses this user is subscribed for,
              or owning, or tutoring.
              This leads to the fact that tutors and owners don't need
              course membership.
          '''
          registered = self.courses.filter(active__exact=True).distinct()
          return (self.tutor_courses() | registered).distinct(f user_courses(self):
          '''
              Returns the list of courses this user is subscribed for,
              or owning, or tutoring.
              This leads to the fact that tutors and owners don't need
              course membership.
          '''
          registered = self.courses.filter(active__exact=True).distinct()
          return (self.tutor_courses() | registered).distinct()
docs: Returns the list of courses this user is subscribed for,
              or owning, or tutoring.
              This leads to the fact that tutors and owners don't need
              course membership.