How can I programmatically make a UICollectionView fill a UITableViewCell?

I'm trying to do something fairly simple, but I keep getting errors.

I have a UITableView with multiple sections. Each section has a header and one UITableViewCell. Within each cell is a UICollectionView. All of these views must be created programmatically (I can't use storyboard solutions).

The problem is when I try to size and position the UICollectionView. I would like the UICollectionView to fill the entire UITableViewCell, so at first I tried to size the UICollectionView in the UITableViewCell's init method using self.frame like so:

var collectionView: UICollectionView?
let collectionViewLayout: UICollectionViewFlowLayout!

override init(style: UITableViewCellStyle, reuseIdentifier: String?) {

        self.collectionViewLayout = UICollectionViewFlowLayout()
        self.collectionViewLayout.sectionInset = UIEdgeInsets(top: 1.0, left: 1.0, bottom: 1.0, right: 1.0)
        self.collectionViewLayout.scrollDirection = .vertical

        super.init(style: style, reuseIdentifier: reuseIdentifier)

        let frame = CGRect(x: 0.0, y: 0.0, width: self.frame.width, height: self.frame.height)
        self.collectionView = UICollectionView(frame: frame, collectionViewLayout: self.collectionViewLayout)

        self.collectionView?.dataSource = self
        self.collectionView?.delegate = self
}

However, I think that the UITableViewCell's frame is not set at this time (the init method call), and so the UICollectionView is sized improperly. Is that correct?

Next, I tried using layout anchors, like so:

collectionView?.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true

This gave me a layout constraint error and said 'UICollectionViewProject[63851:2306772] [LayoutConstraints] Unable to simultaneously satisfy constraints.' I don't understand how thats possible. I only added one constraint, there is nothing in storyboard, what constraints could it possibly be breaking?

Somehow I need to make this UICollectionView the same size as the UITableViewCell and fit inside it perfectly.