code: def get_closest_course_run(course_runs):
      
      if len(course_runs) == 1:
          return course_runs[0]
  
      now = datetime.datetime.now(pytz.UTC)
      # course runs with no start date should be considered last.
      never = now - datetime.timedelta(days=3650)
      return min(course_runs, key=lambda x: abs(get_course_run_start(x, never) - now))
docs: Return course run with start date closest to now.