notification firing 6 times a minute (swift4) - ios

Question

Every time my notification timer goes off it repeats 6 times via in the minute. I only want the notification to fire once per minute. How can I write the code so the notification only goes off once per minute.
import UIKit
class ViewController: UIViewController {
var timer = Timer()
var passingDate : Date?
#IBOutlet var dptext: UITextField!
let datePicker = UIDatePicker()
override func viewDidLoad() {
createDatePicker()
timer = Timer.scheduledTimer(timeInterval: 10, target: self, selector: #selector(ViewController.testDate), userInfo: nil, repeats: true)
}
func createDatePicker() {
datePicker.datePickerMode = .dateAndTime
let toolbar = UIToolbar()
toolbar.sizeToFit()
let doneButton = UIBarButtonItem(barButtonSystemItem: .done, target: nil, action: #selector(donePressed))
toolbar.setItems([doneButton], animated: false)
dptext.inputAccessoryView = toolbar
dptext.inputView = datePicker
}
#objc func testDate() {
if Calendar.current.isDate(datePicker.date, equalTo: Date(), toGranularity: .minute) {
print("success")
if let passingDate = passingDate, Calendar.current.isDate(datePicker.date, equalTo: passingDate, toGranularity: .minute) {
// Previous date existing, and is in the same minute as the current date : do nothing
return
}
passingDate = datePicker.date
print("success")
}
}
#objc func donePressed() {
let dateFormatter = DateFormatter()
dateFormatter.dateStyle = .short
dateFormatter.timeStyle = .short
dptext.text = dateFormatter.string(from: datePicker.date)
self.view.endEditing(true)
}
}

Answer 1

Change the timeInterval from 10 to 60 :
timer = Timer.scheduledTimer(timeInterval: 60, target: self, selector: #selector(ViewController.testDate), userInfo: nil, repeats: true)