Jason Smith3,080 Points
i've messed up somewhere...help!
I thought i was doing this right, but i keep getting 'bummer'!
class Inventory: def __init__(self): self.slots =  def add_item(self, item): self.slots.append(item) class SortedInventory(Inventory): def add_item(item): super().Inventory() slots.append(item)
Alex KoumparosPython Web Development Treehouse Moderator 32,441 Points
You have a couple of errors in your code. Let's work through it by letting Python tell us where the errors are:
When we run your code, this is what we get:
>>> inv = SortedInventory() >>> inv.add_item('sword') Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: add_item() takes 1 positional argument but 2 were given
This is probably a familiar error message. We see it any time create an instance method and forget to define it with the
Fix that and then run the code again. This time:
>>> inv = SortedInventory() >>> inv.add_item('sword') Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/Users/User/inv.py", line 10, in add_item super().Inventory() AttributeError: 'super' object has no attribute 'Inventory'
super() is a way of referring to the parent class. In the case of
SortedInventory, the parent class is
Inventory. This means that when you call
super().Inventory() you are trying to call
Inventory.Inventory(). What you really want to do is call the parent class's version of the same method you are in, which in your case is
Calling the parent's
add_item method will put you in exactly the state you would be in if you were using the base
Inventory class. So then, instead of appending the
slots again, you need to implement the behaviour that makes
SortedInventory different to
Inventory (you need to make the inventory sorted).
Hope these hints point you in the right direction.