Please help, I do not understand this code challenge.

The first part of this code challenge is easy. It simply wants us to create a class called D20 that extends the Die class. Simple. However, I am struggling with the second part of the challenge. I initialized the hand class with the type of dice being D20, imported from the dice.py file. I then set self.die_type to equal D20.

In the roll method I initialized it with the num_dice, being the number of dice to be rolled, as 1. Then used a for loop to append each roll value to self using the D20 object. Lastly the challenge gave us the total property.

Now when I run this in my terminal it seems to work fine. I am able to import both the dice and hand classes and I am able to create an instance of the Hand class no problem. When I check my instance I can see that there are values in my list equal to the number of dice rolled. I am even able to use the roll method on the instance of Hand class as well as use the total property on my instance.

While this seems to all work properly, I get errors when I attempt to submit the code challenge. The main one I usually get is 'Bummer: 'Hand' doesn't have roll method'. I am confused as to what I am missing in my code or if I even implemented it the way that they wanted. I would greatly appreciate if anyone could help me figure out what I am doing wrong. Thank you.

import random


class Die:
    def __init__(self, sides=2):
        if sides < 2:
            raise ValueError("Can't have fewer than two sides")
        self.sides = sides
        self.value = random.randint(1, sides)

    def __int__(self):
        return self.value

    def __add__(self, other):
        return int(self) + other

    def __radd__(self, other):
        return self + other

class D20(Die):
    def __init__(self, sides=20):
        super().__init__(sides)

from dice import D20


class Hand(list):
    def __init__(self, die_type=D20):
        super().__init__()
        self.die_type = die_type

    def roll(self, num_dice=1):
        for _ in range(num_dice):
            self.append(self.die_type())

    @property
    def total(self):
        return sum(self)