Be more readable in this function please.

```php
protected function generateChk(array $datas, $pin)
{
    $key = $datas['id'];
    $key .= number_format($datas['amount'], 2, '.', '');
    $key .= $datas['currency'];
    $key .= rawurlencode($datas['description']);

    if (isset($datas['control']) {
        $key .= $datas['control'];
    }

    if (isset($datas['channel'])) {
        $key .= $datas['channel'];

        if (isset($datas['chlock'])) {
            $key .= $datas['chlock'];
        }
    }

    return md5($key);
}
```