 
 internal final class ProjectPamphletContentViewController: UITableViewController {
   private let dataSource = ProjectPamphletContentDataSource()
-  internal weak var delegate: ProjectPamphletContentViewControllerDelegate!
+  internal weak var delegate: ProjectPamphletContentViewControllerDelegate?
   private let viewModel: ProjectPamphletContentViewModelType = ProjectPamphletContentViewModel()
   private var navBarController: ProjectNavBarViewController!
 

        mainCell.scrollContentOffset(scrollView.contentOffset.y + scrollView.contentInset.top)
    }

    self.delegate.projectPamphletContent(
      self,
      imageIsVisible: scrollView.contentOffset.y < scrollView.bounds.width * 9/16
    )
  }

  @objc private func scrollViewPanGestureRecognizerDidChange(recognizer: UIPanGestureRecognizer) {
    self.delegate.projectPamphletContent(self, scrollViewPanGestureRecognizerDidChange: recognizer)
  }

  private func scrollingIsAllowed(scrollView: UIScrollView) -> Bool {

extension ProjectPamphletContentViewController: VideoViewControllerDelegate {

  internal func videoViewControllerDidFinish(controller: VideoViewController) {
    self.delegate?.videoViewControllerDidFinish(controller)
  }

  internal func videoViewControllerDidStart(controller: VideoViewController) {
    self.delegate?.videoViewControllerDidStart(controller)
  }
}

