Python function returns error 500 with empty body response

If I create a regular HttpTriggered Python function, it behaves differently if the body response is present or absent.

This works via test in the portal or locally, but returns error 500 via postman
```
return func.HttpResponse(status_code=200)
```

This works as expected:
```
return func.HttpResponse(“any-test”, status_code=200)
````