text: import django.dispatch
  
  valid_notification_received = django.dispatch.Signal(providing_args=['instance'])
  invalid_notification_received = django.dispatch.Signal(providing_args=['instance'])
  
  payment_was_approved = django.dispatch.Signal(providing_args=['instance'])
  payment_was_declined = django.dispatch.Signal(providing_args=['instance'])
  payment_was_expired = django.dispatch.Signal(providing_args=['instance'])
  payment_was_flagged = django.dispatch.Signal(providing_args=['instance'])
  