Without it, you get this output

````
Processing document "Acme".
Processing document "AcmeX".
Document classes generated to "..."
````
With it, you get:
````
Processing document "Acme".
Processing document "AcmeX".

Document classes generated to "..."
````

However, it can be made prettier by changing it to:
````php
$output->writeln(array(
    '',
    sprintf('Document classes generated to "<info>%s</info>".', $destPath),
));
````

(I'm not a native, but shouldn't it be "Document classes has been generated to"?)