def test_arg_max(self):
t1 = ('one', 1)
t2 = ('two', 2)
t3 = ('three', 3)
t4 = ('four', 4)
ts = [t2, t1, t3, t4]
arg_max = util.arg_max(ts, lambda x: x[0])
print "arg max:", arg_max
self.assertEqual(arg_max, t2)
self.assertEqual(util.arg_max(ts, lambda x: x[1]), t4)
t = {'a': 1, 'b': 2, 'c': 3, 'd': 1}
arg_max = util.arg_max(t.viewitems(), lambda x: x[1])
self.assertEqual(arg_max[0], 'c')