def to_conll(passage, test=False, tree=False, preprocess=True, **kwargs):
    """ Convert from a Passage object to a string in CoNLL-X format (conll)

    :param passage: the Passage object to convert
    :param test: whether to omit the head and deprel columns. Defaults to False
    :param tree: whether to omit rows for non-primary parents. Defaults to False
    :param preprocess: preprocess the converted dependency graph before returning it?

    :return list of lines representing the dependencies in the passage
    """
    from semstr.conversion.conll import ConllConverter
    return ConllConverter(tree=tree).to_format(passage, test, preprocess=
        preprocess, format=kwargs.get('format'))
