code: def __set_date(self, value):
          '''
          Sets the date of the payment.
          @param value:datetime
          '''
          if not issubclass(value.__class__, date):
              raise ValueError('Invalid date value')
  
          self.__date = valuf __set_date(self, value):
          '''
          Sets the date of the payment.
          @param value:datetime
          '''
          if not issubclass(value.__class__, date):
              raise ValueError('Invalid date value')
  
          self.__date = value
docs: Sets the date of the payment.
          @param value:datetime