Leafo\ScssPhp\Compiler::libAppend PHP Method

    protected function libAppend($args)
    {
        list($list1, $value, $sep) = $args;
        $list1 = $this->coerceList($list1, ' ');
        $sep = $this->listSeparatorForJoin($list1, $sep);
        return [Type::T_LIST, $sep, array_merge($list1[2], [$value])];
    }