Custom Python list sorting
As a side note, here is a better alternative to implement the same sorting:
alist.sort(key=lambda x: x.foo)
Or alternatively:
import operator
alist.sort(key=operator.attrgetter('foo'))
Check out the Sorting How To, it is very useful.
It's documented here.
The sort() method takes optional arguments for controlling the comparisons.
cmp specifies a custom comparison function of two arguments (list items) which should return a negative, zero or positive number depending on whether the first argument is considered smaller than, equal to, or larger than the second argument: cmp=lambda x,y: cmp(x.lower(), y.lower()). The default value is None.