No exact matches in call to class method 'jsonObject'?

Question

Hello I'm new in Swift and I try to write a parser for json through extension with JsonSerialization

I want to implement a function to parse json file and in the same extension to implement the computable var json, which will form json

// Model 
struct Todoitem {
    let id  =  {
      return  UUID().uuidString
    }()
    let text : String
    let importance : Importance
    let deadline : Date?
}

enum Importance {
    case usual, important, unimportant
}
//Parser 

extension Todoitem {
    static func parse(json : Any) -> Todoitem? {
        if let file = try? JSONSerialization.jsonObject(with: json) as? [String : Any] {
            
        }
        return nil
    }
}