code: def create_payment(self, request, amount, description=''):
          
          err = request.POST.get("error", False)
          if err:
              raise PaymentError("Dummy error requested")
  
          return 'fake_transaction_id'
docs: Dummy function for creating a payment through a payment gateway.
          Should be overridden in gateway implementations.
          Can be used for testing - to simulate a failed payment/error,
          pass `error: true` in the request data.