How to use the todoman.formatters.PorcelainFormatter function in todoman

def test_parse_datetime():
    formatter = PorcelainFormatter()

    expected = datetime(2017, 3, 6, 23, 22, 21, 610429, tzinfo=pytz.UTC)
    assert formatter.parse_datetime(1488842541.610429) == expected

    assert formatter.parse_datetime(None) is None
    assert formatter.parse_datetime('') is None

def test_format_datetime():
    formatter = PorcelainFormatter()

    dt = datetime(2017, 3, 8, 0, 0, 17, 457955, tzinfo=pytz.UTC)
    t = 1488931217

    assert formatter.format_datetime(dt) == t

def test_formatting_parsing_consitency():
    tz = pytz.timezone('CET')
    dt = datetime(2017, 3, 8, 21, 6, 19).replace(tzinfo=tz)

    formatter = PorcelainFormatter(tz_override=tz)
    assert formatter.parse_datetime(formatter.format_datetime(dt)) == dt

def test_simple_action(todo_factory):
    formatter = PorcelainFormatter()
    todo = todo_factory(id=7, location='Downtown')

    expected = {
        "completed": False,
        "due": None,
        "id": 7,
        "list": "default",
        "location": "Downtown",
        "percent": 0,
        "priority": 0,
        "summary": "YARR!"
    }

    assert formatter.simple_action('Delete', todo) == \
        json.dumps(expected, indent=4, sort_keys=True)

def callback(click_ctx, color, porcelain, humanize):
        ctx = click_ctx.ensure_object(AppContext)

        if porcelain and humanize:
            raise click.ClickException('--porcelain and --humanize cannot be used'
                                       ' at the same time.')

        if humanize is None:  # False means explicitly disabled
            humanize = ctx.config['main']['humanize']

        if humanize:
            ctx.formatter_class = formatters.HumanizedFormatter
        elif porcelain:
            ctx.formatter_class = formatters.PorcelainFormatter
        else:
            ctx.formatter_class = formatters.DefaultFormatter

        color = color or ctx.config['main']['color']
        if color == 'always':
            click_ctx.color = True
        elif color == 'never':
            click_ctx.color = False

        paths = [
            path for path in glob.iglob(expanduser(ctx.config["main"]["path"]))
            if isdir(path)
        ]
        if len(paths) == 0:
            raise exceptions.NoListsFound(ctx.config["main"]["path"])