code: def deferred_emails():
      
      status = SERVER_STATUS['OK']
      count = Message.objects.deferred().count()
  
      if DEFERRED_WARNING_THRESHOLD <= count < DEFERRED_DANGER_THRESHOLD:
          status = SERVER_STATUS['WARNING']
      if count >= DEFERRED_DANGER_THRESHOLD:
          status = SERVER_STATUS['DANGER']
  
      return {
          'label': 'Deferred Email',
          'status': status,
          'info': 'There are currently {0} deferred messages.'.format(count)
      }
docs: Checks for deferred email, that otherwise fill up the queue.