Reusing same namespace name when writing back XML with xml.etree.ElementTree

[Ofnuts]

I'm editing an XML file with xml.etree.ElementTree. On input the XML has a namespace defined so all tags are of the form

<somenamespace:tag>

When I write the XML back to file, the namespace is called ns0 and the tags look like:

<ns0:tag>

This is valid XML but not as readable. How can i tell Python to use "somenamespace" instead of "ns0"? I tried ET.register_namespace(prefix,namespace) but that doesn't work.

[Ofnuts]

Oops, actually a problem in my code. ET.register_namespace(prefix,namespace) works provided that:

1. It executed before reading the XML
   
2. The namespace string is the correct one.