code: def __field_callback(self, field, event, *args, **kwargs):
          # type: (str, str, *Any, **Any) -> Any
          
          # Get the field callback info
          cb_info = self.context.get_field_callback(field, event)
          if not cb_info:
              # No registered callback
              return True
  
          # Extract information
          callback, if_valid = cb_info
  
          if if_valid and self.state != StoredInstance.VALID:
              # Don't call the method if the component state isn't satisfying
              return True
  
          # Call it
          result = callback(self.instance, field, *args, **kwargs)
          if result is None:
              # Special case, if the call back returns nothing
              return True
  
          return result
docs: Calls the registered method in the component for the given field event
  
          :param field: A field name
          :param event: An event (IPOPO_CALLBACK_VALIDATE, ...)
          :return: The callback result, or None
          :raise Exception: Something went wrong