public static function statusClassFor(int $statusCode): string
    {
        $class = substr((string) $statusCode, 0, 1);
        return self::$statusClass[$class] ?? self::STATUS_CLASS_UNKNOWN;
    }
public static function statusClassFor(int $statusCode): string
    {
        $class = substr((string) $statusCode, 0, 1);
        return self::$statusClass[$class] ?? self::STATUS_CLASS_UNKNOWN;
    }
public static function statusClassFor ( int $ statusCode ) : string { $ class = substr ( ( string ) $ statusCode , 0 , 1 ) ; return self :: $ statusClass [ $ class ] ?? self :: STATUS_CLASS_UNKNOWN ; }
returns status class for given status code

Returns null if given status code is empty.

@api
@param   int  $statusCode
@return  string
@since   4.0.0
returns status class for given status code