[Task]: Update python code and doc strings that uses GCP dependencies

### What needs to happen?

Update python code and doc strings for the modules that uses GCP dependencies. Seems like they use some old conventions and may require some refactoring to keep them up to date.

For example,
1. https://github.com/apache/beam/tree/master/sdks/python/apache_beam/io/gcp/datastore/v1new
2. https://github.com/apache/beam/tree/master/sdks/python/apache_beam/ml/gcp/

### Issue Priority

Priority: 3 (nice-to-have improvement)

### Issue Components

- [ ] Component: Python SDK
- [ ] Component: Java SDK
- [ ] Component: Go SDK
- [ ] Component: Typescript SDK
- [ ] Component: IO connector
- [ ] Component: Beam examples
- [ ] Component: Beam playground
- [ ] Component: Beam katas
- [ ] Component: Website
- [ ] Component: Spark Runner
- [ ] Component: Flink Runner
- [ ] Component: Samza Runner
- [ ] Component: Twister2 Runner
- [ ] Component: Hazelcast Jet Runner
- [ ] Component: Google Cloud Dataflow Runner