To create a GitHub App token (e.g. as part of a login attempt as an app), the app_id (which is expected to be of type int) is used as iss (ref). However, since version 2.11.0 of the pyjwt package, the issuer must be of type str instead, otherwise the following error is raised:

TypeError: Issuer (iss) must be a string.

See jpadilla/pyjwt#1040 for more details on this change.