The Underscore Archives

This is fun, here's another, less pretty one:

attribute_data = mark.fetchall()
keys = (v for k,v in attribute_data)
attributes = dict((key, [k for k,v in attribute_data if v == key]) for  
key in keys)

Alternatively, if you have something like Paste available you can use  
its MultiDict implementation:

from paste.util.multidict import Multidict
attribute_data = mark.fetchall()
attributes = MultiDict(v[::-1] for v in attribute_data).dict_of_lists()

Anyone else want to play?  Come on Tim, you know you want to.

Matt