Azure Function ImportError FunctionRegister when runnning on cloud-CodePudding

I have a durable app function running on versions 3.x written in pyhton that worked fine from the last 1 year. After a new release due to a minor change in software I had to redeploy the function app via

func azure functionapp publish

When I try to run it locally using the Debug tool in VS Code I don't get any error and everything works fine, but now when I run it in cloud (in az portal for instance) i get this error:

Result: Failure Exception: ImportError: cannot import name 'FunctionRegister' from 'azure.functions' (/azure-functions-host/workers/python/3.7/LINUX/X64/azure/functions/init.py). Troubleshooting Guide:

Reference: MSDoc