spacing between collectionview cells wont go away swift code example

Example 1: swift uitableview cell spacing

// Inside UITableViewCell subclass
override func layoutSubviews() {    
    super.layoutSubviews()

    contentView.frame = contentView.frame.inset(by: UIEdgeInsets(top: 8, left: 8, bottom: 8, right: 8))
}

Example 2: how to set the spacing of a collection view swift

// Do any additional setup after loading the view, typically from a nib.
        let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()
        layout.sectionInset = UIEdgeInsets(top: 20, left: 0, bottom: 10, right: 0)
        layout.itemSize = CGSize(width: screenWidth/3, height: screenWidth/3)
        layout.minimumInteritemSpacing = 0
        layout.minimumLineSpacing = 0
        collectionView!.collectionViewLayout = layout