If email forwarding enabled and email address set, then need to add additional forward address(es). Since gmail does not allow more than 1 forwardTo, want to use filters. So, for all incoming mail, want these to be forwarded to the currently set forward addresses and additional email addresses. Currently using Service Account OAuth2 authentication. Am able to retrieve/set forwarding, but not sure how to set/append filter(s) & criteria as shown in table at https://developers.google.com/admin-sdk/email-settings/.
Python service account auth code from: https://stackoverflow.com/a/30039461/3692570
client.CreateFilter(username='username', to='emailaddress', forwardTo='emailaddress') <-- ??
Please help, thank you!