public function setAllowedCss(array $allowed)
    {
        if (is_array($allowed)) {
            foreach ($allowed as $k => $v) {
                self::$allowed_css[$k] = (!is_null($v)) ? $v : $k;
            }
        }
    }
public function setAllowedCss(array $allowed)
    {
        if (is_array($allowed)) {
            foreach ($allowed as $k => $v) {
                self::$allowed_css[$k] = (!is_null($v)) ? $v : $k;
            }
        }
    }
public function setAllowedCss ( array $ allowed ) { if ( is_array ( $ allowed ) ) { foreach ( $ allowed as $ k => $ v ) { self :: $ allowed_css [ $ k ] = ( ! is_null ( $ v ) ) ? $ v : $ k ; } } }
Set the allowed css classes for the extraClass custom setting

@param array $allowed The permissible CSS classes to add
Set the allowed css classes for the extraClass custom setting