class MainViewModel: ObservableObject {
    @ObservedObject var locationManager = LocationManager()
    var cancellable = AnyCancellable {}

    init() {
        cancellable = locationManager.$lastLocation.sink { location in
            log("location observer", .notification, location?.coordinate) // prints a real location
            if location != nil { // locationManager.lastLocation != nil
                self.updateModels { _ in }
            }
        }
    }

    func updateModels(completion: @escaping (String) -> Void) {
        let coordinates: Coordinates = .init(locationManager.lastLocation!.coordinate) // Unexpectedly found nil while unwrapping an Optional value
        ... // some code
    }
}