@classmethod
    def username_max_length(cls):
        raise NotImplementedError('Implement in subclass')
Capture the previously created hold on the participant's credit card.
dataset/ETHPy150Open omab/python-social-auth/social/storage/base.py/UserMixin.username_max_length--crossover with--dataset/ETHPy150Open gratipay/gratipay.com/gratipay/billing/exchanges.py/capture_card_hold