Minimally intrusive XML editing using Python

[Thomas Lotze]

I wonder what Python XML library is best for writing a program that makes
small modifications to an XML file in a minimally intrusive way. By that I
mean that information the program doesn't recognize is kept, as are
comments and whitespace, the order of attributes and even whitespace
around attributes. In short, I want to be able to change an XML file while
producing minimal textual diffs.

Most libraries don't allow controlling the order of and the whitespace
around attributes, so what's generally left to do is store snippets of
original text along with the model objects and re-use that for writing the
edited XML if the model wasn't modified by the program. Does a library
exist that helps with this? Does any XML library at all allow structured
access to the text representation of a tag with its attributes?

Thank you very much.

-- 
Thomas