Get valid datasets and registered parameters.

    Parameters
    ----------
    name : str or None, default None
        Return names and registered parameters of registered datasets. If name
        is specified, only registered parameters of the respective dataset are
        returned.

    Returns
    -------
    dict:
        A dict of all the valid keyword parameters names for the specified
        dataset. If name is set to None, returns a dict mapping each valid name
        to its respective keyword parameter dict. The valid names can be
        plugged in `gluonnlp.model.word_evaluation_model.create(name)`.

def list_datasets(name=None):
    """Get valid datasets and registered parameters.

    Parameters
    ----------
    name : str or None, default None
        Return names and registered parameters of registered datasets. If name
        is specified, only registered parameters of the respective dataset are
        returned.

    Returns
    -------
    dict:
        A dict of all the valid keyword parameters names for the specified
        dataset. If name is set to None, returns a dict mapping each valid name
        to its respective keyword parameter dict. The valid names can be
        plugged in `gluonnlp.model.word_evaluation_model.create(name)`.

    """
    reg = registry.get_registry(Dataset)

    if name is not None:
        class_ = reg[name.lower()]
        return _REGSITRY_NAME_KWARGS[class_]
    else:
        return {
            dataset_name: _REGSITRY_NAME_KWARGS[class_]
            for dataset_name, class_ in registry.get_registry(Dataset).items()
        }