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

[AnandInguva]

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
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• [ ] Component: Typescript SDK
• [ ] Component: IO connector
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[tvalentyn]

Can you give an example of what exactly needs to be updated?

[AnandInguva]

Can you give an example of what exactly needs to be updated?

https://github.com/apache/beam/blob/01cb7e9618db63c79cf1887d43d5b2ec50dc1736/sdks/python/apache_beam/ml/gcp/naturallanguageml.py#L43

https://github.com/apache/beam/blob/01cb7e9618db63c79cf1887d43d5b2ec50dc1736/sdks/python/apache_beam/ml/gcp/naturallanguageml.py#L84

We can update doc strings and add type annotations in the format (pcoll: beam.pvalue.PCollection) instead of pcoll, # type: beam.pvalue.PCollection.