grouping objects by attribute in python

gistfile1.py

import itertools

class A:
    def __init__(self, uniq, key):
        self.uniq = uniq
        self.key = key
    
    def __repr__(self):
        return "%s(%s, %s)" % (self.__class__, self.uniq, self.key)

s = [A(9, 'ankara'), A(87, 'istanbul'), A(25, 'ankara'), A(43, 'antalya'),
     A(3, 'istanbul'), A(99, 'izmir'), A(45, 'bursa'), A(32, 'antalya'),
     A(67, 'izmir')]

print 'default:\n', s, '\n'

grouped_s = [tuple(g) for p, g in \
    itertools.groupby(sorted(s, key=lambda k: k.key), 
                      key=lambda k: k.key)]

print 'grouped:\n'

for p in grouped_s:
    print p
    
"""
default:
[__main__.A(9, ankara), __main__.A(87, istanbul), __main__.A(25, ankara), __main__.A(43, antalya), __main__.A(3, istanbul), __main__.A(99, izmir), __main__.A(45, bursa), __main__.A(32, antalya), __main__.A(67, izmir)]

grouped:

(__main__.A(9, ankara), __main__.A(25, ankara))
(__main__.A(43, antalya), __main__.A(32, antalya))
(__main__.A(45, bursa),)
(__main__.A(87, istanbul), __main__.A(3, istanbul))
(__main__.A(99, izmir), __main__.A(67, izmir))
"""