Fatal error: Can't inherit abstract function

[wkiril]

Fatal error: Can't inherit abstract function SecurityMultiTool\Common\OptionsInterface::setOption() (previously declared abstract in SecurityMultiTool\Common\AbstractOptions) in .../vendor/padraic/security-multitool/library/SecurityMultiTool/Html/Sanitizer.php on line 9

after

new SecurityMultiTool\Html\Sanitizer('cache');

on PHP 5.3.6

Actually it's happening on PHP < 5.3.9