[Py] Problems of XML processing (Dive Into Python)

I am learning how to parse XML content with Python, and the tutorial I've followed is the Dive Into Python. In Chapter 9, most of the examples are clear for a newbie to follow. When I tried the example 9.10 (toxml works on any node), however, unexpected results occurred.

Fortunately, someone had the same problem and there is a solution: Possible error in 'dive into Python' book, help!

The key point is to use documentElement instead of firstChild.

I don't realize the reason yet. More study is necessary for me to understand the whole idea.

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Ref:

• xml.dom — The Document Object Model API
• Python and XML: An Introduction