Domain event + payment created event

payment_created.py

from datetime import datetime
from abc import ABC, ABCMeta, abstractmethod

class DomainEvent(ABC, metaclass=ABCMeta):
    @abstractmethod
    def __init__(self, aggregate_id: str, occurred_at: str):
        self.type = self.__class__.__name__
        self.aggregate_id = aggregate_id
        self.occurred_at = occurred_at

class PaymentCreated(DomainEvent):
    def __init__(self, aggregate_id: str, amount_due: float, occurred_at: str = datetime.utcnow().isoformat()):
        super().__init__(aggregate_id, occurred_at)
        self.amount_due = amount_due