[XML-SIG] Where is the documentation?

[Luiz Siqueira Neto]

I can't find a simple documentation to learn how I use XPath, DOM, SAX in 
Python. I use XPath in Java and it is very easy. I believe XPath in Python is 
very easy too but I need some good start point. If some body have some idea 
or URL will be wellcome.  : )