def L(self):
        return calendar.isleap(self.data.year)
returns an array of decryption factors and a corresponding array of decryption proofs.
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.4/django/utils/dateformat.py/DateFormat.L--crossover with--dataset/ETHPy150Open benadida/helios-server/helios/workflows/homomorphic.py/Tally.decryption_factors_and_proofs