一直試圖打印由以下字典定義的圖形的所有路徑graph = {    "a": [        {"child": "b", "cost": 5},        {"child": "e", "cost": 8}    ],    "b": [        {"child": "c", "cost": 7},        {"child": "f", "cost": 2}    ],    "d": [        {"child": "g", "cost": 3},    ],    "e": [        {"child": "d", "cost": 3},        {"child": "f", "cost": 6}    ],    "f": [        {"child": "c", "cost": 1},    ],    "g": [        {"child": "h", "cost": 10}    ],    "h": [        {"child": "f", "cost": 4}    ]}def print_all_child_paths(graph, node_name):    node = graph[node_name]    if len(node) == 0:        print("No children under this node")    else:        x = 1        for child_node in node:            print("Path number " + str(x) + ": ")            print(node_name + " -> ")            current_node = child_node            while current_node["child"] in graph:                print(current_node["child"] + " -> ")                current_node = graph[current_node["child"]]            print("END.")        x += 1    print("End of paths")print_all_child_paths(graph, "a")當(dāng)我運(yùn)行該函數(shù)時(shí)print_all_child_paths，我以錯(cuò)誤告終list indices must be integers, not str。編譯器指向第 40 行，即 while 循環(huán)定義： while current_node["child"] in graph:我對(duì)錯(cuò)誤感到困惑，因?yàn)檠h(huán)的條件是檢查鍵是否在字典中。誰(shuí)能幫我這個(gè)？提前致謝。