How to write a Python 2.6+ script that gracefully fails with older Python?

Question

I'm using the new print from Python 3.x and I observed that the following code does not compile due to the end=' '.

from __future__ import print_function

import sys
if sys.hexversion < 0x02060000:
    raise Exception("py too old")

...
print("x",end=" ") # fails to compile with py24

How can I continue using the new syntax but make the script fails nicely? Is it mandatory to call another script and use only safe syntax in this one?

Answer 1

The easy method for Python 2.6 is just to add a line like:

b'You need Python 2.6 or later.'

at the start of the file. This exploits the fact that byte literals were introduced in 2.6 and so any earlier versions will raise a SyntaxError with whatever message you write given as the stack trace.