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# I don't know what I did wrong

So I have a challenge that asks me to do this:

Now update Hand in hands.py. I'm going to use code similar to Hand.roll(2) and I want to get back an instance of Hand with two D20s rolled in it. I should then be able to call .total on the instance to get the total of the two dice.

I'll leave the implementation of all of that up to you. I don't care how you do it, I only care that it works.

I have done everything that the challenge asked me but I still get an error saying 'Can't get the length of a 'Hand''

My code is at the bottom of the question.

Can someone help me figure it out?

Thanks!

dice.py
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

return int(self) + other

return self + other

class D20(Die):
def __init__(self):
super().__init__(sides=20)
hands.py
from dice import D20

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

def roll(self, size):
for _ in range(size):
self.append(die_class())

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

MOD

You are almost there. The following needs to be corrected:

• Since the access is from class Hand and not an instance of Hand, the method should be decorated with @classmethod. Also, as a classmethod, use cls instead of self in the parameter list to make it clearer.
• As a classmethod there is no instance to operation on. To create one, use hand = cls()
• As a classmethod, die_class will not have been passed in or defined. Instead, used D20 directly. Also, remember to append to hand instead of self
• Lastly, remember to return the object hand

Post back if you need more help. Good luck!!

I also have this error! It keeps saying

Bummer! Can't get the length of a `Hand`

My dice.py is identical to Andrei's. My hands.py is below, it works just fine in the workspace.

import dice

class Hand(list):
def __init__(self, count=0, diecls=None, *args, **kwargs):
if not diecls:
raise ValueError("You must provide a die class")
if not issubclass(diecls, dice.Die):
raise TypeError("You must provide a type of die as die class")

super().__init__()

for _ in range(count):
self.append(diecls())
self.sort()

@classmethod
def roll(cls, count):
return cls(count=count, diecls=dice.D20)

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

Comment out the line self.sort. The D20 & Die class does not defined the comparison magic methods needed for sort. Actual error:

Traceback (most recent call last):
File "<string>", line 3, in <module>
File "hand.py", line 18, in roll
return cls(count=count, diecls=dice.D20)
File "hand.py", line 14, in __init__
self.sort()
TypeError: unorderable types: D20() < D20()

Great! thanks for this tip. My workspace version had the gt and lt magic methods implemented, so that's why it worked there and not in the challenge.

I guess this challenge was meant to work with minimal changes, I found a shorter solution after reading discussions on other questions for this challenge - you can get away with not even overriding Hand class's init!