$date is a timestamp or a date parsable for strtotime
$country is a iso3361 ALPHA-2 country code
$checkWeekend (optional) is an bolean (true or false) indicate that the class should check if the date is an saturday or sunday
$sundayOnly (optional) is an bolean (true or false) indicate that the weekend check accounts only sundays (some services (e.g. dhl delivers on saturdays too))