def validate(self):
            """
            Validation rules that don't require any extra context go here.
            """
            super().validate()
            if self.default_item_type is not None and not PoeTask.is_task_type(
                self.default_item_type, content_type=str
            ):
                raise ConfigValidationError(
                    "Unsupported value for option `default_item_type`,\n"
                    f"Expected one of {PoeTask.get_task_types(content_type=str)}"
                )
            if self.capture_stdout is not None:
                raise ConfigValidationError(
                    "Unsupported option for sequence task `capture_stdout`"
                )

            Validation rules that don't require any extra context go here.
            
poethepoet/task/sequence.py