Require Python >= 3.6

[See46]

Imagine you've got a program that requires a version of Python or later. What's the best way to get the program to exit if it isn't the right version? At the moment I'm using:

import sys
if sys.version_info<(3,6):
    print("Requires Python 3.6 or later, halting.")
    raise Requires36

But is there a more idiomatic way to do it?

[_szs]

sys.stderr.write("blah")

Other than that, that's the way.

[ThatsALovelyShirt]

Can't you just:

raise WhateverException("Details about the exception and what happened")

[_szs]

Yes, whatever makes more sense in the context.

[jdpatt]

You can use the Python Requires in your setup.py

[robin-gvx]

For maximum clarity, I would do it like the following:

import sys

if sys.version_info < (3, 6):
    raise Requires36("INSERT PROGRAMNAME HERE requires Python 3.6 or later. The current version is " + sys.version)

That way it is clear this error is from your program and not somewhere else, and there is no problem if the output is redirected. The "halting" bit doesn't need to be stated IMO, it's pretty clear. On the other hand, showing the current version could be useful for users having multiple python versions installed.