What do trashfolder and spamfolder do for Gmail repositories

[Arjun]

Hi 

I have a nametrans setup as follows

  nametrans = lambda f: '[Gmail]/' + f if f in ['Drafts', 'Starred', 'Important', 'Spam', 'Trash', 'All Mail', 'Sent Mail'] else f

I use notmuch and alot on the maildir. To delete emails, I have afew setup to move emails into the local Trash folder.

Do I need to set 

    trashfolder=Trash
    spamfolder=Spam

or do I need to set

    trashfolder='[Gmail]/Trash'
    spamfolder='[Gmail]/Spam'

Does this only come into play when I set the IMAP flag \Deleted on messages? Is there a way to do this using afew (though I realize this part of the question is not related to this list)?

Arjun