Works for me.

I think I prefer the multi-line spelling I copied from somewhere else. It seems like it might be easier to maintain?

    python_requires=', '.join([
        '>=2.7',
        '!=3.0.*',
        '!=3.1.*',
        '!=3.2.*',
        '!=3.3.*',
        '!=3.4.*',
    ]),

With a formatter like black this will go anyway in one line unless one forces this line to be unformatted (with the special '# fmt: off' comment).
I would go with one line.
Hopefully this line will be soon: python_requires='>3.6' ;)
Just my 2c.

@jamadden I like the multi-line spelling, and I agree that it's easier to maintain -- if you do that manually.

I don't maintain Python versions manually; I have check-python-versions for that. It writes python_require expressions for me. I have plans to teach it to write those multi-line expressions you prefer, but I haven't done that yet.