return self.discount_price, self.discount_rate
Actually when you wanna get result you wanna return the values. so use given above code after
self.discount_price=float(self.price*self.discount_rate/100)-self.price
your full updated code is below:
class Shop:
def __init__(self,name,item_no,price,discount):
self.name=name
self.item_no=item_no
self.price=float(price)
def discount(self,discount_rate,discount_price):
self.discount_rate=float(0.15)
self.discount_price=float(self.price*self.discount_rate/100)-self.price
return self.discount_price, self.discount_rate
item1 = Shop('bag','9988','800','0.15')
print(item1.discount("",""))