It does not get written. The net effect is that the module is parsed
and compiled again and again by each Python process that imports it
(but only once per process!). This does not slow down program
execution in the long run but it does slow down program start-up
(which can be quite significant in the case of scripts that import
many modules but only need a tiny bit of information from each of
them).
--Guido van Rossum, CWI, Amsterdam <Guido.van.Rossum@cwi.nl>
URL: <http://www.cwi.nl/cwi/people/Guido.van.Rossum.html>