code: def retrieve_activity_profile_ids(self, activity, since=None):
          
          if not isinstance(activity, Activity):
              activity = Activity(activity)
  
          request = HTTPRequest(
              method="GET",
              resource="activities/profile"
          )
          request.query_params["activityId"] = activity.id
  
          if since is not None:
              request.query_params["since"] = since
  
          lrs_response = self._send_request(request)
  
          if lrs_response.success:
              lrs_response.content = json.loads(lrs_response.data)
  
          return lrs_response
docs: Retrieve activity profile id(s) with the specified parameters
  
          :param activity: Activity object of desired activity profiles
          :type activity: :class:`tincan.activity.Activity`
          :param since: Retrieve activity profile id's since this time
          :type since: str | unicode
          :return: LRS Response object with list of retrieved activity profile id's as content
          :rtype: :class:`tincan.lrs_response.LRSResponse`