Returning values URLSession.shared.dataTask in swift

I just started coding in Swift and I have the following code which parses JSON

func parse (latitude: Double, longtitude: Double){


    let jsonUrlString = "https://api.darksky.net/forecast/apiKey/\(latitude),\(longtitude)"

    guard let url = URL(string: jsonUrlString) else{
        return
    }

    var information: forecast?
    URLSession.shared.dataTask(with: url) { (data, res, err) in

        guard let data = data else { 
              return
        }

        do {
            let json = try JSONDecoder().decode(forecast.self, from: data)
            self.info = json

        } catch {
            print("didnt work")
        }

    }.resume()

    processJson(info)
}

My problem is that I want to pass data that is stored in JSON to a variable in the class to be processed using processJson function but since the dataTask function does not return any values, and JSON variable is locally stored I cannot process info variable outside the class (it always returns nil). I was wondering what is the solution to this problem? I'm facing the same problem with weather.getCoordinate().