Using conversion functions

Your client library calls a gRPC service and gets back low-level protobuf messages. The conversion functions this library provides translate those into the high-level Python wrappers, so the rest of your code — and your users — work with wrappers instead of protobuf.

Convert a single message

response = await self._stub.GetMetricSample(request)
return metric_sample_from_proto(response.metric_sample)

Convert a list of messages

response = await self._stub.ListMetricSamples(request)
return [metric_sample_from_proto(s) for s in response.samples]

You don't handle unknown or invalid values here

The conversion function already deals with them: it keeps an enum value your version doesn't recognize as a plain int, and returns an Invalid* wrapper instead of raising when data is malformed. You just return the wrapper. Deciding what those cases mean is up to your users — see the User Guide.