googleapis/google-api-python-client — reverse-engineered prompt

Build me a Python client library for Google's discovery based APIs. I want developers to be able to install it with pip, create a service object for a Google API from its discovery document, and call that API in a normal Python way without having to fetch discovery data every time.

Please make it feel like an official, reliable library rather than a demo. It should support modern Python versions, include packaged discovery documents, clear setup instructions for Mac, Linux, and Windows, and have enough tests and sample code that someone can see how to use it quickly. Add documentation that explains when this general client is useful, and when people should choose the newer Google Cloud specific client libraries instead.

Keep the scope focused on maintaining and using discovery based Google APIs. Don’t add unrelated new product features. Look up current Google API client docs online if you need to.