sort help

[Larry Martell]

I currently have 3 lists of lists and I sort them based on a common
field into a single list like this:

        def GetObjKey(a):
            return a[2]

        sorted(a + b + c, key=GetObjKey)

Which works just fine.

But now, I need to have just the first list (a) also sub sorted by
another field and I can't quite figure out how to do this.

So for example, if my initial data was this (I'll only show the fields
involved with the sort - the first number is a[2] above and the second
is the new additional sorting field, only present in a)

a[1, 4]
a[1, 2]
a[2, 3]
a[2, 1]
a[5, 6]
a[5, 2]
b[2]
b[5]
c[1]
c[6]

Then I'd want my sorted list to be this:

a[1,2]
a[1,4]
c[1]
a[2,1]
a[2,3]
b[2]
a[5,2]
a[5,6]
b[5]
c[6]

I hope that's clear.

So is there some pythonic way to sort this without resorting to a
brute force old fashioned plow through the data?