     /// - Parameter closure: Block to be runned.
     /// - Returns: Newly created promise.
     @discardableResult
-    public func callback(_ closure: @escaping animClosure) -> anim {
+    func callback(_ closure: @escaping animClosure) -> anim {
         var settings = anim.defaultSettings
         settings.delay = 0
         settings.duration = 0

    /// - Parameter milliseconds: Milliseconds to wait.
    /// - Returns: Newly created promise.
    @discardableResult
    public func wait(_ seconds: TimeInterval) -> anim {
        var settings = anim.defaultSettings
        settings.delay = seconds
        settings.duration = 0

    /// - Parameter closure: Animation block.
    /// - Returns: Newly created promise.
    @discardableResult
    func then(_ closure: @escaping animClosure) -> anim {
        let nextAnim = anim(closureWithoutProcess: closure)
        chain(to: nextAnim)
        return nextAnim
