How to use the conllu.parser.parse_conllu_plus_fields function in conllu

def test_simple(self):
        data = dedent("""\
            # global.columns = ID FORM UPOS HEAD DEPREL MISC PARSEME:MWE
            1\tDer\tDET\t2\tdet\t_\t*
        """)
        self.assertEqual(
            parse_conllu_plus_fields(string_to_file(data)),
            ["id", "form", "upos", "head", "deprel", "misc", "parseme:mwe"]
        )

def test_empty(self):
        self.assertEqual(parse_conllu_plus_fields(string_to_file("")), None)
        self.assertEqual(parse_conllu_plus_fields(string_to_file(None)), None)

def test_empty_columns(self):
        data = dedent("""\
            # global.columns =
            1\tDer\tDET\t2\tdet\t_\t*
        """)
        self.assertEqual(parse_conllu_plus_fields(string_to_file(data)), None)

def parse_incr(in_file, fields=None, field_parsers=None, metadata_parsers=None):
    if not hasattr(in_file, 'read'):
        raise FileNotFoundError("Invalid file, 'parse_incr' needs an opened file as input")

    if not fields:
        fields = parse_conllu_plus_fields(in_file, metadata_parsers=metadata_parsers)

    for sentence in parse_sentences(in_file):
        yield TokenList(*parse_token_and_metadata(
            sentence,
            fields=fields,
            field_parsers=field_parsers,
            metadata_parsers=metadata_parsers
        ))