Error while trying to shuffle a deck of cards

I am trying to shuffle a deck of cards and I keep getting this error which I don’t know how to solve. I am new to python and OOP so I think this should just be something that I overlooked.

This is my code:

class Deck:
    def __init__(self):
        self.deck = []

        for suit in suits:
            for rank in ranks:
                card_created = Card(suit, rank)
                self.deck.append(card_created)

    def __str__(self):
        deck_comp = ""
        for card in self.deck:
            deck_comp += "\n"+ card.__str__()
        return "The deck has: " + deck_comp

    def shuffle(self):
        random.shuffle(self.deck)

    def deal_one(self):
        return self.deck.pop()

new_deck = Deck()

print(new_deck.shuffle())

When I run the program I only get "None". However, before shuffling the deck, I get all the existing cards in order.

Does anyone know how to fix this?

>Solution :

Your shuffle() function doesn’t return any value (and neither does random.shuffle(), which shuffles the list in-place).

Instead, you should perform the call to .shuffle() and print() on separate lines:

new_deck.shuffle()
print(new_deck.deck)