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[Flavio Barbara]

* The xml.etree.cElementTree module deprecated in 3.3.

It was removed and reverted in Python 3.9. Now is marked for deletion in Pythom 3.10.
But on some systems (mine: debian stable) this library was already deleted in Python 3.9 and "import xml.etree.cElementTree" actually import the new implementation, xml.etree.ElementTree.
It happens that the new library has a different interfaces since:
* Methods Element.getchildren(), Element.getiterator() and ElementTree.getiterator() deprecated in 2.7 and 3.2. They were deprecated in the documentation only, and started to emit a warning in 3.8. Use list(elem) or iteration instead of getchildren(), methods iter() instead of getiterator().

https://bugs.python.org/issue36543

Builder use the method getiterator(), so it crashes on start up.

I attach a small patch I used on my system. But I think that cannot be use in a general case.

Cheers
Flavio Barbara