为什么我不能打印我的函数的结果？

Question

如何显示clazz的值？

def k_nearest_neighbors(node, nodes, k=3):
    x1, y1 = node
    distances = []
    for x2, y2, node_cls in nodes:
        distance = abs(x1 - x2) + abs(y1 - y2)
        distances.append((node_cls, distance))
        distances = sorted(distances, key=lambda x: x[1], reverse=False)
        classes = [x[0] for x in distances[:k]]
        
cards = [
    (2, 0, "schilten"), (0, 1, "schilten"), (0, 2, "schilten"),
    (9, 2, "rosen"), (1, 13, "rosen"),
    (3, 3, "eichel"),
    (5, 5, "schellen"),
    
]
card = (2, 1)
clazz = k_nearest_neighbors(card, cards)

print(clazz) 不起作用。