@property
def is_free_kindle(self) -> bool:
    return ((self.price == 0) and (self.total_order == 0) and (self.subtotal_price_item == 0) and (self.destination == '') and self.status.startswith('デジタル注文:') and (self.billing_amount == '0') and (self.credit_card_billing_date == '') and (self.credit_card_billing_amount == '') and (self.credit_card_identity == ''))
@property
def is_free_kindle(self) -> bool:
    return ((self.price == 0) and (self.total_order == 0) and (self.subtotal_price_item == 0) and (self.destination == ) and self.status.startswith('デジタル注文:') and (self.billing_amount == '0') and (self.credit_card_billing_date == ) and (self.credit_card_billing_amount == ) and (self.credit_card_identity == ))