How to use the pyperf._cli.format_metadata function in pyperf

cpus = args.affinity
    if cpus:
        if not set_cpu_affinity(cpus):
            print("ERROR: failed to set the CPU affinity")
            sys.exit(1)
    else:
        cpus = get_isolated_cpus()
        if cpus:
            set_cpu_affinity(cpus)
            # ignore if set_cpu_affinity() failed

    run = pyperf.Run([1.0])
    metadata = run.get_metadata()
    if metadata:
        print("Metadata:")
        for line in format_metadata(metadata):
            print(line)

    if filename:
        run = run._update_metadata({'name': 'metadata'})
        bench = pyperf.Benchmark([run])
        bench.dump(filename)

def _display_common_metadata(metadatas, lines):
    if len(metadatas) < 2:
        return

    for metadata in metadatas:
        # don't display name as metadata, it's already displayed
        metadata.pop('name', None)

    common_metadata = _common_metadata(metadatas)
    if common_metadata:
        format_title('Common metadata', lines=lines)
        empty_line(lines)

        format_metadata(common_metadata, lines=lines)

    for key in common_metadata:
        for metadata in metadatas:
            metadata.pop(key, None)

if use_title:
        show_filename = (data.get_nsuite() > 1)
        show_name = not data.has_same_unique_benchmark()
        if not show_filename and stats:
            show_filename = (len(data) > 1)

        suite = None
        for index, item in enumerate(data):
            lines = []

            if show_metadata:
                metadata = metadatas[index]
                if metadata:
                    empty_line(lines)
                    lines.append("Metadata:")
                    format_metadata(metadata, lines=lines)

            bench_lines = format_benchmark(item.benchmark,
                                           hist=hist,
                                           stats=stats,
                                           dump=dump,
                                           checks=checks,
                                           result=result,
                                           display_runs_args=display_runs_args)

            if bench_lines:
                empty_line(lines)
                lines.extend(bench_lines)

            if lines:
                bench_lines = lines
                lines = []