PlanetTableViewController.swift

private func fetchPlanets() {
    do {
        try planetsController.performFetch()
        tableView.reloadData()
    }
    catch {
        NSLog("Fetching failed with error \(error as NSError).")
    }
}
    
override func numberOfSections(in tableView: UITableView) -> Int {
    return 1
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return planetsController.sections?[0].numberOfObjects ?? 0
}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "PlanetCellIdentifier", for: indexPath)
    cell.accessoryType = .disclosureIndicator
    cell.textLabel?.text = planetsController.object(at: indexPath).name
    return cell
}
    
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    scenePresenter?.presentDetailedInfo(for: planetsController.object(at: indexPath))
}