code: def get_participants_for_gradebook(gradebook_id, person=None):
      
      if not valid_gradebook_id(gradebook_id):
          raise InvalidGradebookID(gradebook_id)
  
      url = "/rest/gradebook/v1/book/{}/participants".format(gradebook_id)
      headers = {}
  
      if person is not None:
          headers["X-UW-Act-as"] = person.uwnetid
  
      data = get_resource(url, headers)
  
      participants = []
      for pt in data["participants"]:
          participants.append(_participant_from_json(pt))
  
      return participants
docs: Returns a list of gradebook participants for the passed gradebook_id and
      person.