Variable name has a typo, but code still works. Why?

[mateus]

mateus wrote:
> print "hello world"
>
> I have a nested loop where the outer loop iterates over key value pairs
> of a dictionary and the inner loop iterates over a list each list of
> which is a mapped value from the dictionary
>
>     def showReport(self):
>         for dev, sessions in self.logger.items():
>             for tree in session:
>                 self.addTestItem(self, tree)
>
> What I don't understand is why this executes w/o any problems when
> "sessions" was spelled as plural (sessionS) while later being spelled
> in the singular (session).
>
> Is there some type of name resolution of local variables where Python
> makes assumptions?

A few specs that I forgot to mention.

Version: python-2.4.2
OS: Librix (Gentoo (Linux))