         
         // CollectionView
         view.addSubview(collcetionView)
-        collcetionView.backgroundColor = .blue
         collcetionView.snp.makeConstraints { (make) in
             make.left.bottom.centerX.equalToSuperview()
             make.top.equalTo(tabBar.snp.bottom)

private let mainCellReuseID = UICollectionViewCell.nameOfClass

class BQMainViewController: UIViewController {
    
    // MARK: - Properties
    fileprivate lazy var subControllers: [UIViewController] = {

        let subContr = subControllers[indexPath.item]
        if !subContr.isViewLoaded {
            addChildViewController(subContr)
            cell.addSubview(subContr.view)
            subContr.view.snp.makeConstraints({ (make) in
                make.edges.equalToSuperview()
            })
            subContr.didMove(toParentViewController: self)
        } else {
            cell.addSubview(subContr.view)
            subContr.view.snp.makeConstraints({ (make) in
                make.edges.equalToSuperview()
            })
