如何访问嵌套字典中的值: Swift

let nestedDictionary = [
    "key1": [
        "nestedKey1": "value1",
        "nestedKey2": "value2"
    ],
    "key2": [
        "nestedKey3": "value3",
        "nestedKey4": "value4"
    ]
]

let value = nestedDictionary["key1"]

let nestedValue = value?["nestedKey1"]

if let value = nestedDictionary["key1"],
   let nestedValue = value["nestedKey1"] {
    print(nestedValue) // 输出: value1
}

if let nestedValue = nestedDictionary["key1"]?["nestedKey1"] {
    print(nestedValue) // 输出: value1
}