When\When::prepareItemsList PHP Method

    protected static function prepareItemsList($items, $delimiter = ",", $validator = null)
    {
        $_items = false;
        if (is_numeric($items)) {
            $_items = array(intval($items));
        }
        if (is_string($items) && $_items === false) {
            // remove any accidental delimiters
            $items = trim($items, $delimiter);
            $_items = self::createItemsList($items, $delimiter);
        }
        if (is_array($items)) {
            $_items = $items;
        }
        if (is_array($_items) && Valid::itemsList($_items, $validator)) {
            return $_items;
        }
        return false;
    }