[Biopython-dev] ImportWarning is new on Python 2.5

[Peter]

Hi Eric,

I've just been running the test suite on Python 2.4 (on CentOS 5.4)
and noticed you use ImportWarning (which was added in Python 2.5) in
Bio/Phylo/PhyloXMLIO.py

Although we are going to phase out support for Python 2.4, we still
need to keep things compatible for now.

Are you happy to switch this to a different warning for now, and add a
TODO comment to put it back to an ImportWarning once we drop Python
2.4 support?

Thanks

Peter