Change color of individual section in UICollectionView

Question

My question for today that I have been trying to figure out for a while but what is really buggy or doesn't work because I'm unclear on how to implement it is how to change the color of the individual sections in a collection view. For example, I would like sections 0-2 to be orange, 3-5 to be blue, 6-8 to be pink, and 9-11 to be green.

I have tried to implement the code in these two repositories. The first one after implementing worked somewhat but is very buggy when I try to scroll the collection view, but I think I didn't implement it correctly. The second one after trying to implement it, nothing showed up so I don't think I did that correctly either. My goal is to hard-set the color for each section.

Here is the code for creating the collection view:

let friendsCollectionView: UICollectionView = {
        let layout = UICollectionViewFlowLayout()
        //also tried let layout = SectionBackgroundFlowLayout() and let layout = ColorFlowLayout()
        layout.scrollDirection = .horizontal
        let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
        cv.translatesAutoresizingMaskIntoConstraints = false
        cv.register(FriendsCell.self, forCellWithReuseIdentifier: "cell")
        cv.layer.cornerRadius = 10
        cv.isPagingEnabled = true
        cv.showsHorizontalScrollIndicator = false
        return cv
       }()

This is an addition that I pulled from the example repo of the second repo:

class ColorFlowLayout: UICollectionViewFlowLayout {

// MARK: prepareLayout

override func prepare() {
    super.prepare()

//        minimumLineSpacing = 8.0
//        minimumInteritemSpacing = 8.0
//        sectionInset = UIEdgeInsetsMake(8, 8, 8, 8)
//
//        let width = (UIScreen.main.bounds.width / 3) - 2 * 8.0
//        itemSize = CGSizeMake(width, 100)

    //register(SCSBCollectionReusableView.self, forDecorationViewOfKind: "sectionBackground")

    register(UICollectionView.self, forDecorationViewOfKind: "sectionBackground")
}

// MARK: layoutAttributesForElementsInRect
override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
    let attributes = super.layoutAttributesForElements(in: rect)
    var allAttributes = [UICollectionViewLayoutAttributes]()

    if let attributes = attributes {

        for attr in attributes {
            // Look for the first item in a row
            // You can also calculate it by item (remove the second check in the if below and change the tmpWidth and frame origin
            if (attr.representedElementCategory == UICollectionElementCategory.cell && attr.frame.origin.x == self.sectionInset.left) {

                // Create decoration attributes
                let decorationAttributes = SCSBCollectionViewLayoutAttributes(forDecorationViewOfKind: "sectionBackground", with: attr.indexPath)
                // Set the color(s)
                if (attr.indexPath.section % 2 == 0) {
                    decorationAttributes.color = UIColor.orange //Just two different colors to test at the moment
                } else {
                    decorationAttributes.color = UIColor.blue
                }

                // Make the decoration view span the entire row
                let tmpWidth = self.collectionView!.contentSize.width
                let tmpHeight = self.collectionView!.contentSize.height // or attributes.frame.size.height instead of itemSize.height if dynamic or recalculated


                decorationAttributes.frame = CGRect(x: 0, y: attr.frame.origin.y - self.sectionInset.top, width: tmpWidth, height: tmpHeight)

                // Set the zIndex to be behind the item
                decorationAttributes.zIndex = attr.zIndex - 1

                // Add the attribute to the list
                allAttributes.append(decorationAttributes)
            }
        }
        // Combine the items and decorations arrays
        allAttributes.append(contentsOf: attributes)
    }

    return allAttributes
}

}

Let me know if you have any questions or if I could provide any more information. All help is much appreciated!