RPG Roller Code Challenge

import random


class Die:
    def __init__(self, sides=2, value=0):
        if sides < 2:
            raise ValueError("Can't have fewer than two sides")
        if not isinstance(sides, int):
            raise ValueError("Sides must be a whole number")
        if not isinstance(value, int):
            raise ValueError("Value must be a whole number")
        self.sides = sides
        self.value = value or 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, size=None):
        self.size = size

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

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

#    def __len__(self):
#        return len(self)