Even if getHeaders() has security/performance concerns, the better solution is to make it an alias to the newer headers.get() in this case. Keeping the old API is a small hassle to a handful of developers but breaking existing code puts a much bigger burden on a lot more users.

If you (either directly or from SerpApi) are supporting the urllib3 folks (through a Tidelift subscription), then yes, that is a valid point.

Otherwise, I'd say that's a very brave comment you are making.