How to update a value in a nested dictionary given path fragment in Swift?

Dictionary+Extension.swift

extension Dictionary {
    subscript(jsonDict key: Key) -> [String:Any]? {
        get {
            return self[key] as? [String:Any]
        }
        set {
            self[key] = newValue as? Value
        }
    }
}

var dict: [String: Any] = [
    "countries": [
        "japan": [
            "capital": [
                "name": "Tokyo",
            ],
        ]
    ],
    "airports": ""
]

dict[jsonDict: "countries"]?[jsonDict: "japan"]?[jsonDict: "capital"]?["name"] = "Berlin"

let name = dict[jsonDict: "countries"]?[jsonDict: "japan"]?[jsonDict: "capital"]?["name"]

print(name)

// Refer to https://stackoverflow.com/a/41543070/9315497 
// https://talk.objc.io/episodes/S01E31-mutating-untyped-dictionaries