What is wrong with my code? It keeps on saying "Try again"

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):
        super().__init__(sides=20)

from dice import D20

class Hand(list):
    def __init__(self, x):
        super().__init__()
        self.extend(x)

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

    @classmethod
        def roll(cls,size, die_class =D20):
            x = []
            for _ in range(size):
                x.append(die_class())
        return cls(x)

class Hand(list):
    @property
    def total(self):
        return sum(self)