打印类实例列表的随机实例，但得到RecursionError python3

import random

class cards():

    def __init__(self,val,suit):
        self.val = val
        self.suit = suit

    def __repr__(self):
       return str(self)

deck = []
card_val = ['A','2','3','4','5','6','7','8','9','10','J','Q','K']
card_suit = ['♦','♥','♠','♣']

for x in card_val:
    for y in card_suit:
        card = cards(x,y)
        deck.append(card)

print(random.choice(deck))

尝试打印时，出现以下错误：

RecursionError: maximum recursion depth exceeded while calling a Python object

我对类实例很陌生。我环顾四周，找不到有效的答案。任何帮助，将不胜感激。