     /// Updates the animators.
     func updateAnimators() {
         let t = progress * totalDuration
-        for a in animators {
-            a.seek(to: t)
+        for v in animators {
+            v.seek(to: t)
         }
     }
     
     /// Updates the plugins.
     func updatePlugins() {
         let t = progress * totalDuration
-        for p in plugins where p.requirePerFrameCallback {
-            p.seek(to: t)
+        for v in plugins where v.requirePerFrameCallback {
+            v.seek(to: t)
         }
     }
 }

        return isNavigationController || isTabBarController
    }
    
    /// Indicates whether the from view controller is full screen.
    internal var fromOverFullScreen: Bool {
        guard let v = fromViewController else {
            return false
        }
        
        return !isContainerController && (.overFullScreen == v.modalPresentationStyle || .overCurrentContext == v.modalPresentationStyle)
    }
    
    /// Indicates whether the to view controller is full screen.
    internal var toOverFullScreen: Bool {
        guard let v = toViewController else {
            return false
        }
        
        return !isContainerController && (.overFullScreen == v.modalPresentationStyle || .overCurrentContext == v.modalPresentationStyle)
    }
    
    /// An initializer.

    /// An optional completion callback.
    internal var completionCallback: ((Bool) -> Void)?
    
    /// An Array of MotionPreprocessors used during a transition.
    internal lazy var preprocessors = [MotionPreprocessor]()
    
