If a company didn't hire me because they idiotically interpreted "I am a python developer" to mean "I would try to build a rendering engine in python" then I'd say that's probably a bullet dodged.
I'd interpret it as "I don't build rendering engines but I build other stuff for which python is a good fit", but maybe that's just me being weird.
The trope about great programmers being people who reverse binary trees in their sleep and being able to swap ecosystems at the drop of a hat needs to die. Great programmers specialise.
You aren't honestly trying to sift out clueless prospective employers out by their ability to parse a title, are you?
The advice here is to put focus on ability to write software, and experience using python as a tool to do so, rather than implying that your ability is limited to python.
Absolutely, which is why I didn't stop at "I am a developer". That "who is good at Python" bit is definitely important.
However, seeing yourself as a "Python developer" rather than "a developer who is good at Python" makes it look like you see every problem as something you'll solve using Python. That's bad. That will put a lot of companies off hiring you (companies that believe in a 'best tool for the job' approach anyway, and those are the ones you probably want to work for).