code: def __set_method(self, value):
          '''
          Sets the amount of the payment.
          '''
          if value not in [PAYMENT_METHOD_OTHER, PAYMENT_METHOD_CARD,
                           PAYMENT_METHOD_CHEQUE, PAYMENT_METHOD_CASH, ]:
              raise ValueError('Invalid amount value')
  
          self.__method = valuf __set_method(self, value):
          '''
          Sets the amount of the payment.
          '''
          if value not in [PAYMENT_METHOD_OTHER, PAYMENT_METHOD_CARD,
                           PAYMENT_METHOD_CHEQUE, PAYMENT_METHOD_CASH, ]:
              raise ValueError('Invalid amount value')
  
          self.__method = value
docs: Sets the amount of the payment.