docs: def get_campus_permissions(calendar_id, campus_code):
      """
      :return: a list of sorted trumba.Permission objects
               corresponding to the given campus calendar.
               None if error, [] if not exists
      raise DataFailureException if the request failed.
      """
      if is_bot(campus_code):
          return get_bot_permissions(calendar_id)
      elif is_sea(campus_code):
          return get_sea_permissions(calendar_id)
      elif is_tac(campus_code):
          return get_tac_permissions(calendar_id)
      else:
          logger.warn(
              "Calling get_campus_permissions with invalid campus code: %s"
              % campus_code)
          return None