How to use the twarc.json2csv.get_headings function in twarc

def on_hit(self, hit, tweet_count):
        # Cycle tweet id files
        if tweet_count % self.max_per_file == 0:
            if self.file:
                self.file.close()
            self.file = open(
                os.path.join(self.dataset_path, 'tweets-{}.csv'.format(str(self.file_count).zfill(3))), 'w')
            self.sheet = csv.writer(self.file)
            self.sheet.writerow(json2csv.get_headings())
            self.file_count += 1
        # Write to tweet file
        self.sheet.writerow(json2csv.get_row(json.loads(hit.tweet), excel=True))

def get_headings(extra_headings=None):
    fields = json2csv.get_headings()
    if extra_headings:
        fields.extend(extra_headings)
    return fields

def _header_row(self):
        return twarc.json2csv.get_headings()

parser.error("csv output not available for %s" % command)
    elif args.format in ("csv", "csv-excel"):
        csv_writer = csv.writer(fh)
        csv_writer.writerow(get_headings())

    line_count = 0
    file_count = 0
    for thing in things:

        # rotate the files if necessary
        if args.output and args.split and line_count % args.split == 0:
            file_count += 1
            fh = codecs.open(numbered_filepath(args.output, file_count), 'wb', 'utf8')
            if csv_writer:
                csv_writer = csv.writer(fh)
                csv_writer.writerow(get_headings())

        line_count += 1

        # ready to output

        kind_of = type(thing)
        if kind_of == str_type:
            # user or tweet IDs
            print(thing, file=fh)
            log.info("archived %s" % thing)
        elif 'id_str' in thing:
            # tweets and users
            if (args.format == "json"):
                print(json.dumps(thing), file=fh)
            elif (args.format == "csv"):
                csv_writer.writerow(get_row(thing))