def last(conf):
    """How long you have kept signing in."""
    try:
        v2ex = V2ex(conf.config)
        v2ex.login()
        last_date = v2ex.get_last()
        click.echo(last_date)
    except KeyError:
        click.echo('Keyerror, please check your config file.')
    except IndexError:
        click.echo('Please check your username and password.')
How long you have kept signing in.