type 'ViewController' does not conform to protocol 'AddAnItemDelegate'

Não consigo localizar o porque da mensagem de erro abaixo: type 'ViewController' does not conform to protocol 'AddAnItemDelegate'

Segue o código do ViewController.swift:

import UIKit


protocol AddAMealDelegate {
    func add(meal: Meal)
}


class ViewController: UIViewController,
                        UITableViewDataSource,
                        UITableViewDelegate, AddAnItemDelegate {

     var items = [ Item(name: "Eggplant Brownie", calories: 10),
        Item(name: "Zucchini Muffin", calories: 10),
        Item(name: "Cookie", calories: 10),
        Item(name: "Coconut oil", calories: 500),
        Item(name: "Chocolate frosting", calories: 1000)
    ]
    @IBOutlet var nameField: UITextField!
    @IBOutlet var happinessField: UITextField!
    var delegate:AddAMealDelegate?
    var selected = Array<Item>()

    @IBOutlet var tableView: UITableView?

    func addnew(item: Item) {
        items.append(item)
        if let table = tableView {
            table.reloadData()
        } else {
            Alert(controller: self).show()
        }
    }

    func tableView(tableView: UITableView,
        numberOfRowsInSection section: Int) -> Int {
            return items.count
    }

    func tableView(tableView: UITableView,
                    cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let row = indexPath.row
        let item = items[ row ]
        var cell = UITableViewCell(style: UITableViewCellStyle.Default,
                                    reuseIdentifier: nil)
        cell.textLabel!.text = item.name
        return cell
    }

    func tableView(tableView: UITableView,
                    didSelectRowAtIndexPath indexPath: NSIndexPath) {
        if let cell = tableView.cellForRowAtIndexPath(indexPath){
            if (cell.accessoryType == UITableViewCellAccessoryType.None) {
                cell.accessoryType = UITableViewCellAccessoryType.Checkmark
                selected.append(items[indexPath.row])
            } else {
                cell.accessoryType = UITableViewCellAccessoryType.None
                if let position = find(selected, items[indexPath.row]) {
                    selected.removeAtIndex(position)
                } else {
                    Alert(controller: self).show()
                }
            }
        } else {
            Alert(controller: self).show()
        }
    }

    override func viewDidLoad() {
        let newItemButton = UIBarButtonItem(title: "new item",
            style: UIBarButtonItemStyle.Plain,
            target: self,
            action: Selector("showNewItem"))
        navigationItem.rightBarButtonItem = newItemButton
    }

    @IBAction func showNewItem() {
        let newItem = NewItemViewController(delegate: self)
        if let navigation = navigationController {
            navigation.pushViewController(newItem, animated: true)
        } else {
            Alert(controller: self).show()
        }
    }

    func getMealFromForm() -> Meal? {
        if nameField == nil || happinessField == nil {
            return nil
        }

        let name = nameField!.text
        let happiness = happinessField!.text.toInt()
        if happiness == nil {
            return nil
        }

        let meal = Meal(name: name, happiness: happiness!)
        meal.items = selected
        println("eaten: \(meal.name) \(meal.happiness) \(meal.items)")
        return meal
    }

    @IBAction func add() {
        if let meal = getMealFromForm() {
            if let meals = delegate {
                meals.add(meal)
                if let navigation = self.navigationController {
                    navigation.popViewControllerAnimated(true)
                } else {
                    Alert(controller: self).show(
                        message: "Unexpected error, but the meal was added.")
                }
                return
            }
        }
        Alert(controller: self).show()
    }
}

Segue o Código do NewItemViewController.swift:

import UIKit

protocol AddAnItemDelegate {
    func addNew(item:Item)
}

class NewItemViewController: UIViewController {
    let delegate:AddAnItemDelegate?
    init(delegate:AddAnItemDelegate) {
        self.delegate = delegate
        super.init(nibName: "NewItemViewController", bundle: nil)
    }

    required init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    @IBOutlet var nameField:UITextField?
    @IBOutlet var caloriesField:UITextField?
    @IBAction func addNewItem() {
        if nameField == nil || caloriesField == nil {
            return
        }
        let name = nameField!.text
        let calories = NSString(string: caloriesField!.text).doubleValue
        let item = Item(name: name, calories: calories)
        if delegate == nil {
            return
        }
        delegate!.addNew(item)
        if let navigation = navigationController {
            navigation.popViewControllerAnimated(true)
        }
    }
}