Why lxml.find() calls return False..

https://mailman-mail5.webfaction.com/pipermail/lxml/2005-August/000332.html

What happens is that an element evaluates to False if it has no 
children, and True if it does. The presence of text content, attributes 
or a tail does not affect the boolean status; if no elements exist it'll 
still be False.

find() has the behavior to return None if the value cannot be found. You 
can change your tests to something like:

if xmldoc.find('child') is not None:
     ...

to check whether you have a child.