public function offsetSet($offset, $value)
    {
        if (is_null($offset)) {
            $this->lines[] = $value;
        } else {
            $index = $this->findLine($offset);

            if ($index >= 0) {
                $this->lines[$index] = "{$offset}={$value}";
            } else {
                $this->lines[] = "{$offset}={$value}";
            }
        }
    }