How do i access all email?

First review labels:

gmail.labels.all => 
["travel", "[Gmail]/All Mail", "[Gmail]/Drafts", "[Gmail]/Important", 
"[Gmail]/Sent Mail", "[Gmail]/Spam", "[Gmail]/Starred", "[Gmail]/Trash"]

From the issues I think these are language dependent so, if you're in France it's not likely to be "[Gmail]/All Mail"

Second - access all mail via label

gmail.mailbox("[Gmail]/All Mail").count