code: def read_value(self, offset=0):
          
          try:
              val = self._object.ReadValue(
                  {'offset': dbus.UInt16(offset, variant_level=1)},
                  dbus_interface='org.bluez.GattDescriptor1')
              return val
          except dbus.exceptions.DBusException as e:
              error = _error_from_dbus_error(e)
              self.service.device.descriptor_read_value_failed(self, error=error)
docs: Reads the value of this descriptor.
  
          When successful, the value will be returned, otherwise `descriptor_read_value_failed()` of the related
          device is invoked.