     weak internal var revealController: PBRevealViewController?
     internal var toViewController: UIViewController?
     internal var fromViewController: UIViewController?
-    internal var completion: ((_: Void) -> Void)? = nil
-
-    init(revealController: PBRevealViewController, containerView: UIView, fromViewController: UIViewController, toViewController: UIViewController, completion: @escaping (_: Void) -> Void) {
+    internal var completion: (() -> Void)? = nil
+
+    init(revealController: PBRevealViewController, containerView: UIView, fromViewController: UIViewController, toViewController: UIViewController, completion: @escaping () -> Void) {
         
         self.revealController = revealController
         self.containerView = containerView

     - Returns:
        A block to be inserted in the view animation completion.
     */
    @objc optional func revealController(_ revealController: PBRevealViewController, completionBlockFor operation: PBRevealControllerOperation, from fromViewController: UIViewController, to toViewController: UIViewController) -> ((_: Void) -> Void)?

    /**
     Ask for a block with animation and completion while replacing/pushing child view controllers, please add the final block to your completion.

     - Returns:
        A block to be inserted in the view animation.
     */
    @objc optional func revealController(_ revealController: PBRevealViewController, animationBlockFor operation: PBRevealControllerOperation, from fromViewController: UIViewController, to toViewController: UIViewController) -> (() -> Void)?

    /**
     Ask for completion block while pushing main view controller.
