OOP Python add some attribute to the base class?

I am learning OOP with python .trying with small console application Stock

class Stock(object):

    def __init__(self, stockName, stockLimit, inStock, rentPrice):

        self.stockName  = stockName   # private
        self.stockLimit = stockLimit  # private
        self.inStock    = inStock     # private
        self.rentPrice  = rentPrice   # private

    def inputStock(self, nProduct):

        if(nProduct >= (self.stockLimit - self.inStock)):
            self.inStock = self.stockLimit
        else:
            self.inStock += nProduct 

    def invoice(self, nDay):
        return self.rentPrice * nDay


class StockProduct(Stock):

    def __init__(self, factor):
        # the base-class constructor:
        Stock.__init__(self, stockName, stockLimit, inStock, rentPrice)
        self.factor = factor # Extra for this stock

    def invoice(self, nDay):
        return Stock.invoice(self, nDay) * self.factor

class StockMaterial(Stock):

    def __init__(self,factor):
        # the base-class constructor:
        Stock.__init__(self, stockName, stockLimit, inStock, rentPrice)
        self.factor = factor # Extra开发者_运维百科 for this stock

    def invoice(self,nDay):
        return Stock.invoice(self, nDay)*self.factor

if __name__ == "__main__":

    N = nDay = 0
    myStock = Stock("stock111", 500, 200, 400000)
    N = float(raw_input("How many product into stock: "+str(myStock.stockName)+" ? "))
    myStock.inputStock(N)
    nDay = int(raw_input("How many days for rent : "+str(myStock.stockName)+" ? "))
    print "Invoice for rent the stock: "+str(myStock.stockName)+ " = "+ str(myStock.invoice(nDay))

    StockProduct = StockProduct("stock222",800, 250, 450000, 0.9)

    N = float(raw_input("How many product into stock: "+str(StockProduct.stockName)+" ? "))
    StockProduct.inputStock(N)
    nDay = int(raw_input("How many days for rent : "+str(StockProduct.stockName)+" ? "))
    print "Invoice for rent the stock: "+str(StockProduct.stockName)+ " = "+ str(StockProduct.invoice(nDay))

I have two questions:

1. with my method invoice, how Can I do method overloading in python ?

2. I added some attribute in the child I got the following error message:

   StockProduct = StockProduct("stock222",800, 250, 450000, 0.9)
   TypeError
   
   error: __init__() takes exactly 2 arguments (6 given)
   

What I should do here?

Anybody can help me please?

Thank in advance

1. The overloaded invoice in the derived class should work fine.

2. Your base class constructor needs to have all the parameters, so :

   class StockProduct(Stock):
       def __init__(self, stockName, stockLimit, inStock, rentPrice, factor):
           # the base-class constructor:
           Stock.__init__(self, stockName, stockLimit, inStock, rentPrice)
           self.factor = factor
   
       def invoice(self, nDay):
           return Stock.invoice(self, nDay) * self.factor
   

1 - Yes, you can do method overloading in python.

2 - Your child class changed the method signature. You should declare it as

def __init__(self, stockName, stockLimit, inStock, rentPrice, factor):

if you want to construct it with all the arguments from the parent class plus some extra.