Do Python libraries need a ersion number?

Eric S. Raymond esr at
Fri Dec 15 10:00:27 UTC 2017

Hal Murray <hmurray at>:
> esr at said:
> > If you look in the library Python directories you will see that this is not
> > done.  It would make writing imports a problem, as "ntp-1.0" is not parsed
> > as a single token in Python. 
> So we have to use things like ntp, ntp2, ...  ?
> Do Python libraries get used by other projects?  (as compared to the project 
> that installs them)  How do they change the API?

You can load a library even if its API version has changed.  It's up
to library authors to provide a version explicitly, if they choose to,
and library clients to check it, if they choose to.

In practice this is seldom done; instead APIs are kept backward-compatible.
Practice gets some help here from Python being a language that does not
conduce to bulky code; thus, nobody minds leaving old entry points in
place very much.
		<a href="">Eric S. Raymond</a>

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