code: def report_last_seen_message(current):
      
      sbs = Subscriber(current).objects.filter(channel_id=current.input['channel_key'],
                                               user_id=current.user_id)[0]
      sbs.last_seen_msg_time = current.input['timestamp']
      sbs.save()
      current.output = {
          'status': 'OK',
          'code': 200}
docs: Push timestamp of latest message of an ACTIVE channel.
  
      This view should be called with timestamp of latest message;
      - When user opens (clicks on) a channel.
      - Periodically (eg: setInterval for 15secs) while user staying in a channel.
  
  
      .. code-block:: python
  
          #  request:
              {
              'view':'_zops_last_seen_msg',
              'channel_key': key,
              'key': key,
              'timestamp': datetime,
              }
  
          #  response:
              {
              'status': 'OK',
              'code': 200,
              }