create_expires_generator has been renamed to create_token_expires_in_generator. If you haven't created a subclass of
Flask AuthorizationServer, or you haven't overwrote create_expires_generator, there is nothing to change.
If you need to rewrite the create_expires_generator method, you need to change it to:
class MyAuthorizationServer(AuthorizationServer):
def create_token_expires_in_generator(self, app):
...
https://git.io/vhL75