final public static function get() : Calculator
    {
        if (self::$instance === null) {
            self::$instance = self::detect();
        }

        return self::$instance;
    }
final public static function get() : Calculator
    {
        if (self::$instance === null) {
            self::$instance = self::detect();
        }

        return self::$instance;
    }
final public static function get ( ) : Calculator { if ( self :: $ instance === null ) { self :: $ instance = self :: detect ( ) ; } return self :: $ instance ; }
Returns the Calculator instance to use.

If none has been explicitly set, the fastest available implementation will be returned.

@return Calculator
Returns the Calculator instance to use .