[Yum] Repodata question

[Jarret R]

After repository creation, there are several files in the repodata 
directory. repomd.xml contains hashes of the other .xml.gz files. If we 
look at the entry for primary.xml we get this:

<data type="primary">
   <location href="repodata/primary.xml.gz"/>
   <checksum type="sha">af43b5994495060dd222f6a56684194742c54d78</checksum>
     <timestamp>1103135373</timestamp>
     <open-checksum 
type="sha">b4098edfc3a1d5786eec0495862f3a84eec6b0c5</open-checksum>
</data>

Now if I do a sha1sum of primary.xml.gz I get this:

wume4:~/btyum/rsync/i386/repodata% sha1sum primary.xml.gz
af43b5994495060dd222f6a56684194742c54d78  primary.xml.g

Which matches the first checksum number. I was wondering how the second 
is generated? A google search for "open checksum" just brings up repo 
files :).

I am making changes to the primary.xml file and I need to be able to 
update the repomd.xml file. My application is in Python, so pointing to 
code examples would be awesome.


Thanks,
Jarret Raim