docs: def _callbacks_cleanup(cnx, callback_ids):
      '''
      Unregister all the registered callbacks
  
      :param cnx: libvirt connection
      :param callback_ids: dictionary mapping a libvirt object type to an ID list
                           of callbacks to deregister
      '''
      for obj, ids in callback_ids.items():
          register_name = REGISTER_FUNCTIONS[obj]
          deregister_name = register_name.replace('Reg', 'Dereg')
          deregister = getattr(cnx, deregister_name)
          for callback_id in ids:
              deregister(callback_id)