如何在Swift中将嵌套字典转换为平面字典？

func flattenDictionary(_ dictionary: [String: Any], parentKey: String = "") -> [String: Any] {
    var flattenedDictionary = [String: Any]()
    
    for (key, value) in dictionary {
        var newKey = key
        
        if !parentKey.isEmpty {
            newKey = parentKey + "." + key
        }
        
        if let nestedDictionary = value as? [String: Any] {
            let nestedFlattenedDictionary = flattenDictionary(nestedDictionary, parentKey: newKey)
            flattenedDictionary.merge(nestedFlattenedDictionary) { (_, new) in new }
        } else {
            flattenedDictionary[newKey] = value
        }
    }
    
    return flattenedDictionary
}

// 示例用法
let nestedDictionary: [String: Any] = [
    "key1": "value1",
    "key2": [
        "nestedKey1": "nestedValue1",
        "nestedKey2": "nestedValue2"
    ],
    "key3": "value3"
]

let flattenedDictionary = flattenDictionary(nestedDictionary)
print(flattenedDictionary)