Dealing with IMAP mailbox name case sensitivty

I have a python script using imaplib that connects to a gmail account and sorts emails based on '+' tags found in the email address. For example: emails sent to myaccount+root.foo.bar@gmail.com get moved to root\foo\bar.

My logic goes as follows: extract tags -> attempt to create folders -> copy message to folder.

Ocassionally an email will come in with the same tags, but different casing. myaccount+root.FOO.BAR@gmail.com, for example, and leads to this output:

#Attempting to creating folder 'root/FOO/BAR'
('NO', ['[ALREADYEXISTS] Folder name conflicts with existing folder name. (Failure)'])
#Copying message to folder 'root/FOO/BAR'
('NO', ['[TRYCREATE] No folder root/FOO/BAR (Failure)'])

So it fails to create the folder, because a folder with the same name already exists (just with different case), but the copy fails because the explicit folder doesn't exist.

Is there some clever way that I can figure out the correct case of the existing folder so I can move the message without issue?

Note: This isn't as easy as just forcing all tags to low开发者_如何学编程ercase. A User connects to the account with an email client and ocassioanlly manually makes folders with whatever casing makes sense to them at the time.

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So Google complains that the folder already exists, but then gives an error when you try to move something into it? Terrific.

IMAP has a "LIST" command to list available mailboxes (folders):

https://www.rfc-editor.org/rfc/rfc3501#section-6.3.8

How to access that depends on your IMAP client library. Here are a couple of examples.