let pinCodeDecorator: DDPinCodeDecoratorProtocol = DDPinCodeDecorator(frame: frame)

/*
The array with secure images.
The number of pictures is equal to the number of symbols (icons).
*/
var secureImagesArray: [UIImage] { get set }

/*
The image for initial display of all icons
*/
var emptyImage: UIImage { get set }

/*
Optional
Called when all symbols are set
*/
func provideResult(module: DDPinCodeDecoratorProtocol, result: String)

/*
The view that the decorator manages.
*/
var view: UITextField? { get }

func addSymbol(_ symbol: String)
func delSymbol()

let pinCodeDecorator: DDPinCodeDecoratorProtocol = DDPinCodeDecorator(frame: .zero)

pinCodeDecorator.delegate = self
pinCodeDecorator.secureImagesArray = appleImages    // is not empty array needed
pinCodeDecorator.emptyImage = emptyAppleImage       // is not nil needed
pinCodeDecorator.successImage = successAppleImage
pinCodeDecorator.unsuccessImage = unsuccessAppleImage
pinCodeDecorator.padding = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)
pinCodeDecorator.shadow = DDPinCodeDecoratorShadowModel(color: UIColor.black,
opacity: 0.5,
offSet: CGSize(width: 1, height: 1),
radius: 5,
scale: true)
pinCodeDecorator.font = UIFont.systemFont(ofSize: 24)
pinCodeDecorator.symbolOffset = UIOffset(horizontal: 0, vertical: 3)
pinCodeDecorator.secureDelay = 0.2
pinCodeDecorator.isEnableKeyboard = false

guard let appleView = pinCodeDecorator.view else { return }
pinCodeContenView.addSubview(appleView)

...

// in some method someButtonDidTouch e.g.
pinCodeDecorator.addSymbol(symbol)
// or
pinCodeDecorator.delSymbol()

...

// delegate method called
func provideResult(module: DDPinCodeDecoratorProtocol, result: String) {
    if module === self.pinCodeDecorator {
        if result == "1234" {
            module.showSuccess()
        } else {
            module.showUnsuccess()
            animate(module: module)
        }
    }
}

/*
The view that the decorator manages.
*/
var view: UITextField? { get }

/*
The string that contains entered characters
Default is ""
*/
var resultString: String { get }

/*
The receiver’s delegate.
*/
var delegate: DDPinCodeDecoratorOutput? { get set}

/*
The font used to display the text.
Default is UIFont.systemFont(ofSize: 14)
*/
var font: UIFont? { get set }

/*
The shadow used to display the icons.
Default is:
color = UIColor.black
opacity = 0.5
offSet = CGSize(width: 1.0, height: 1.0)
radius = 5
scale = true
*/
var shadow: DDPinCodeDecoratorShadowModel? { get set }

/*
The delay from the symbol is displayed until the secure image is displayed
Default is 0.2
*/
var secureDelay: Double? { get set }

/*
A Boolean value that determines whether the keyboard is accessible
Default is true
*/
var isEnableKeyboard: Bool? { get set }

/*
The array with secure images.
The number of pictures is equal to the number of symbols (icons).
*/
var secureImagesArray: [UIImage] { get set }

/*
The image for initial display of all icons
*/
var emptyImage: UIImage { get set }

/*
The image of all icons to display successful input
*/
var successImage: UIImage { get set }

/*
The image of all icons to display unsuccessful input
*/
var unsuccessImage: UIImage { get set }

func addSymbol(_ symbol: String)
func delSymbol()

func showSuccess()
func showUnsuccess()

/*
Do not allow user to enter symbols
*/
func stopTapping()
func allowTapping()

func showKeyboard()
func hideKeyboard()

/*
Display all icons as initial and remove all symbols
*/
func clear()

/*
Optional
Insets for all icons
Default is .zero
*/
var padding: UIEdgeInsets { get set }
var symbolOffset: UIOffset? { get set }