How can this sample be modified to be used in a serverless environment?

When running Flask (or other webserver) in an Azure function (or similar) I guess the web session based cache in the sample can not be used because of the ephemeral nature of Cloud functions.
How to get this sample and this particular authorization flow work in a serverless environment?
Is it a matter of implementing your own cache where you store and handle the access token and refresh token?
In that case, would you suggest that cache implementation to inherit from _SerializableTokenCache_?