I have used a PageStreamer in the ListAll method in the event that there are more then 1000 files in the directory this will ensure that we get them all back. PageStreaming is much easier then having to deal with the nextPageToken yourself.
After we have all of the results then PrettyPrint is running recursively to request all of the files from within any directories.
By using PageStreamer you can retrieve all of the rows for your request rather then having to worry about the nextPageToken yourself.
Note: I am not responsible for the usage of your quota if you print everything 🙂