def register_task(name, dataclass=None):
    """
    New tasks can be added to fairseq with the
    :func:`~fairseq.tasks.register_task` function decorator.

    For example::

        @register_task('classification')
        class ClassificationTask(FairseqTask):
            (...)

    .. note::

        All Tasks must implement the :class:`~fairseq.tasks.FairseqTask`
        interface.

    Args:
        name (str): the name of the task
    """

    def register_task_cls(cls):
        if name in TASK_REGISTRY:
            raise ValueError("Cannot register duplicate task ({})".format(name))
        if not issubclass(cls, FairseqTask):
            raise ValueError(
                "Task ({}: {}) must extend FairseqTask".format(name, cls.__name__)
            )
        if cls.__name__ in TASK_CLASS_NAMES:
            raise ValueError(
                "Cannot register task with duplicate class name ({})".format(
                    cls.__name__
                )
            )
        TASK_REGISTRY[name] = cls
        TASK_CLASS_NAMES.add(cls.__name__)

        if dataclass is not None and not issubclass(dataclass, FairseqDataclass):
            raise ValueError(
                "Dataclass {} must extend FairseqDataclass".format(dataclass)
            )

        cls.__dataclass = dataclass
        if dataclass is not None:
            TASK_DATACLASS_REGISTRY[name] = dataclass

            cs = ConfigStore.instance()
            node = dataclass()
            node._name = name
            cs.store(name=name, group="task", node=node, provider="fairseq")

        return cls

    return register_task_cls

    New tasks can be added to fairseq with the
    :func:`~fairseq.tasks.register_task` function decorator.

    For example::

        @register_task('classification')
        class ClassificationTask(FairseqTask):
            (...)

    .. note::

        All Tasks must implement the :class:`~fairseq.tasks.FairseqTask`
        interface.

    Args:
        name (str): the name of the task
    
understand_icl/fairseq/fairseq/tasks/__init__.py