code: def _open_interface(self, client, uuid, iface, key):
          
  
          conn_id = self._validate_connection('open_interface', uuid, key)
          if conn_id is None:
              return
  
          conn_data = self._connections[uuid]
          conn_data['last_touch'] = monotonic()
  
          slug = self._build_device_slug(uuid)
  
          try:
              resp = yield self._manager.open_interface(conn_id, iface)
          except Exception as exc:
              self._logger.exception("Error in manager open interface")
              resp = {'success': False, 'reason': "Internal error: %s" % str(exc)}
  
          message = {'type': 'response', 'operation': 'open_interface', 'client': client}
          message['success'] = resp['success']
  
          if not message['success']:
              message['failure_reason'] = resp['reason']
  
          self._publish_response(slug, message)
docs: Open an interface on a connected device.
  
          Args:
              client (string): The client id who is requesting this operation
              uuid (int): The id of the device we're opening the interface on
              iface (string): The name of the interface that we're opening
              key (string): The key to authenticate the caller