def view_top_five_employees(given_date):
    """
    Returns five top employees that have longest presence time at given date.
    """
    days = get_all_days()
    if given_date not in days:
        LOG.debug('Wrong date (%s) or date doesn\'t exist.', given_date)
        abort(404)
    return sorted(
        get_employees(given_date).items(),
        key=lambda val: val[1],
        reverse=True
    )
def view_all_days():
    """
    Dates listing for dropdown.
    """
    return sorted(get_all_days().items())