[xml] Xpath issues with libxml2

[Alex Boese <alexanderashleyboese gmail com>]

Forgive me if this is a deprecated approach (as I am not fully aware), but I was utilizing "default" libxml2 
bindings (not lxml) in Python to retrieve xml fragments via xpath functions. Normally this seems to work 
fine, but with namespace declarations this seems especially problematic as nothing ever returns and nothing 
errors. Would it be possible to confirm what correct functions and order of operations would be for this? 
Even if the example is C, I can translate that to Python.

Thank you in advance.
-Alex