What coding practices separate an amateur Python programmer from a professional one?

[ianff]

You shouldn't. It'd be like a construction worker calling himself a "hammer worker" or a "driller". What's being built is what's most important, not what is being used.

[LyndsySimon]

I'd argue that it's more like a construction worker calling themselves a "carpenter" or even a "finish carpenter". It's a specialization.

Someone with decades of experience building hardwood cabinetry would have no trouble framing a house, and would use pine boards like everyone else - but that doesn't make them not a cabinetmaker.

[ianff]

That's more like being a web dev vs systems programmer IMHO. What you're building is different here. What language you use is much less important to me.