app/Family.php
public static function marriageDateComparator(): Closure
    {
        return static function (Family $x, Family $y): int {
            return Date::compare($x->getMarriageDate(), $y->getMarriageDate());
        };
    }
public static function marriageDateComparator(): Closure
    {
        return static function (Family $x, Family $y): int {
            return Date::compare($x->getMarriageDate(), $y->getMarriageDate());
        };
    }
public static function marriageDateComparator ( ) : Closure { return static function ( Family $ x , Family $ y ) : int { return Date :: compare ( $ x -> getMarriageDate ( ) , $ y -> getMarriageDate ( ) ) ; } ; }
A closure which will compare families by marriage date.

@return Closure
A closure which will compare families by marriage date .