Writing backwards compatible code - when?

[Kent Johnson]

> Bob Greschke wrote:
>> Is there a list of all of the Python commands and modules that tell when 
>> (what version) they were added to Python?  I was hoping the new Essential 
>> Reference would have it, but it doesn't.

The Library Reference page for a module or built-in often documents the 
version when any change was made. You can also read through the What's 
New documents for each release to see what changed in that release.

Kent