how to use reduce in python

gistfile1

class A:
    @property
    def value(self):
        return 1

sample_list = [A(), A(), A()]

print reduce(lambda x, y: x + y.value, sample_list, 0)
print reduce(lambda x, y: x + y, map(lambda x: x.value, sample_list))
print sum(map(lambda x: x.value, sample_list))