I get a compiler error "type VendingMachine does not conform to protocol vendingMachineType"

import Foundation

// Protocols

protocol VendingMachineType {
    var selection: [VendingSelection] { get }
    var inventory: [VendingSelection: ItemType] { get set }
    var amountDeposited: [Double] { get set }

    init(inventory : [VendingSelection: ItemType])

    func vend (selection: VendingSelection, quantity: Double) throws
    func deposit (amount: Double)
}

protocol ItemType {
    var price: Double { get }
    var quantity : Double { get set }
}

// Error Types

enum InventoryError: ErrorType {
    case InvalidResource
    case ConversionError
    case InvalidKey
}

// Helper Class

class PlistConveter {
    class func dictionaryFromFile(resource: String, ofType type: String) throws -> [String : AnyObject] {
        guard let path = NSBundle.mainBundle().pathForResource(resource, ofType: type) else {
            throw InventoryError.InvalidResource }
        guard let dictionary = NSDictionary(contentsOfFile: path), let castDictionary = dictionary as? [String : AnyObject] else {
            throw InventoryError.ConversionError }
        return castDictionary
    }
}

class inventoryUnarchiver {
    class func vendingInventoryFromDictionary(dictionary: [String : AnyObject]) throws -> [VendingSelection : ItemType] {
        var inventory: [VendingSelection: ItemType] = [:]

    for (key,value) in dictionary {
        if let itemDict = value as? [String : Double], let price = itemDict["price"], let quantity = itemDict["quantity"] {
            let item = VendingItem(price: price, quantity: quantity)

            guard let key = VendingSelection(rawValue: key) else {
                throw InventoryError.InvalidKey
            }
            inventory.updateValue(item, forKey: key)
        }
    }
    return inventory
    }
}

// Concrete Types

enum VendingSelection: String {
    case Soda
    case DietSoda
    case Chips
    case Cookie
    case Sandwich
    case Wrap
    case CandyBar
    case PopTart
    case Water
    case FruitJuice
    case SportsDrink
    case Gum
}

struct VendingItem : ItemType {
    var price: Double
    var quantity: Double
}

class VendingMachine: VendingMachineType {
    let selection: [VendingSelection] = [.Soda, .DietSoda, .Chips, .Cookie, .Sandwich, .Wrap, .CandyBar, .PopTart, .Water, .FruitJuice, .SportsDrink, .Gum]
    var inventory: [VendingSelection : ItemType]
    var amountDeposited: Double = 10.0

    required init(inventory: [VendingSelection : ItemType]) {
        self.inventory = inventory
    }

    func vend(selection: VendingSelection, quantity: Double) throws {
        // Add code
    }
    func deposit(amount: Double) {
        // Add code
    }
}