Change bar button color of navigation bar in GMSPlacePickerViewController

Question

I want to change the color of cancel and search icon in GMSPlacePickerViewController navigation bar. I tried changing the background color to test but it isn't working.

func textFieldDidBeginEditing(_ textField: UITextField) {
    let config = GMSPlacePickerConfig(viewport: nil)
    let placePicker = GMSPlacePickerViewController(config: config)
    placePicker.delegate = self
    placePicker.navigationController?.navigationBar.backgroundColor = UIColor.black
    placePicker.navigationController?.navigationBar.isTranslucent = false
    present(placePicker, animated: true, completion: nil)

}