classmethodデコレータを使ったコンストラクタのオーバーライドの例

constructor_override.py

# See https://pandanote.info/?p=9956 for details.

class Expense:
    amount = 0
    reason = ""
    remark = ""
    def __init__(self, amount, reason, remark):
        self.amount = amount
        self.reason = reason
        self.remark = remark

    @classmethod
    def no_remark(cls, amount, remark):
        return cls(amount, "", remark)

    @classmethod
    def copy(cls, expense):
        return cls(expense.amount, expense.reason, expense.remark)