Use of unresolved identifier. (doesn't make sense) - xcode

Question

I am making a game using Sprite Kit in swift that has objects falling down the screen that need to be caught by the player(Labeled Person) at the bottom. I am trying do remove the falling objects from the screen when they contact the player but I cant call on the falling object (labeled Ice) inside of the function did begin contact. I am able to call on other objects like the person or the score label but not the object falling down the screen (Labeled Ice). Why is this I will post my full code below. This has really been bugging me. (ps. I am given the error "use of unresolved identifier")
import SpriteKit
struct physicsCatagory {
static let person : UInt32 = 0x1 << 1
static let Ice : UInt32 = 0x1 << 2
static let IceTwo : UInt32 = 0x1 << 3
static let IceThree : UInt32 = 0x1 << 4
static let Score : UInt32 = 0x1 << 5
}
class GameScene: SKScene, SKPhysicsContactDelegate {
var scorenumber = Int()
var person = SKSpriteNode(imageNamed: "Person")
let Score = SKSpriteNode()
var ScoreLable = SKLabelNode()
override func didMoveToView(view: SKView) {
self.scene?.backgroundColor = UIColor.purpleColor()
physicsWorld.contactDelegate = self
self.scene?.size = CGSize(width: 640, height: 1136)
Score.size = CGSize(width: 648, height: 1)
Score.position = CGPoint(x: 320, y: -90)
Score.physicsBody = SKPhysicsBody(rectangleOfSize: Score.size)
Score.physicsBody?.affectedByGravity = false
Score.physicsBody?.dynamic = false
Score.physicsBody?.categoryBitMask = physicsCatagory.Score
Score.physicsBody?.collisionBitMask = 0
Score.physicsBody?.contactTestBitMask = physicsCatagory.IceThree
Score.color = SKColor.blueColor()
self.addChild(Score)
person.position = CGPointMake(self.size.width/2, self.size.height/12)
person.setScale(0.4)
person.physicsBody = SKPhysicsBody(rectangleOfSize: person.size)
person.physicsBody?.affectedByGravity = false
person.physicsBody?.categoryBitMask = physicsCatagory.person
person.physicsBody?.contactTestBitMask = physicsCatagory.Ice
person.physicsBody?.collisionBitMask = physicsCatagory.Ice
person.physicsBody?.dynamic = false
ScoreLable.position = CGPoint(x: self.frame.width / 2, y: 1000)
ScoreLable.text = "\(scorenumber)"
ScoreLable.fontColor = UIColor.yellowColor()
ScoreLable.fontSize = 100
ScoreLable.fontName = "Zapfino "
self.addChild(ScoreLable)
var IceThreeTimer = NSTimer.scheduledTimerWithTimeInterval(0.5, target: self, selector: ("spawnThirdIce"), userInfo: nil, repeats: true)
self.addChild(person)
}
func didBeginContact(contact: SKPhysicsContact) {
let firstBody = contact.bodyA
let secondBody = contact.bodyB
if firstBody.categoryBitMask == physicsCatagory.person && secondBody.categoryBitMask == physicsCatagory.IceThree || firstBody.categoryBitMask == physicsCatagory.IceThree && secondBody.categoryBitMask == physicsCatagory.person{
scorenumber++
ScoreLable.text = "\(scorenumber)"
CollisionWithPerson(firstBody.node as! SKSpriteNode, Person: secondBody.node as! SKSpriteNode)
}
if firstBody.categoryBitMask == physicsCatagory.Score && secondBody.categoryBitMask == physicsCatagory.IceThree ||
firstBody.categoryBitMask == physicsCatagory.IceThree && secondBody.categoryBitMask == physicsCatagory.Score{
self.view?.presentScene(EndScene())
}
}
func CollisionWithPerson (Ice: SKSpriteNode, Person: SKSpriteNode){
Person.removeFromParent()
}
func spawnThirdIce(){
var Ice = SKSpriteNode(imageNamed: "Ice")
Ice.setScale(0.9)
Ice.physicsBody = SKPhysicsBody(rectangleOfSize: Ice.size)
Ice.physicsBody?.categoryBitMask = physicsCatagory.IceThree
Ice.physicsBody?.contactTestBitMask = physicsCatagory.person | physicsCatagory.Score
Ice.physicsBody?.affectedByGravity = false
Ice.physicsBody?.dynamic = true
let MinValue = self.size.width / 8
let MaxValue = self.size.width - 20
let SpawnPoint = UInt32(MaxValue - MinValue)
Ice.position = CGPoint(x: CGFloat(arc4random_uniform(SpawnPoint)), y: self.size.height)
self.addChild(Ice)
let action = SKAction.moveToY(-85, duration: 2.5)
let actionDone = SKAction.removeFromParent()
Ice.runAction(SKAction.sequence([action,actionDone]))
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
for touch in touches {
let location = touch.locationInNode(self)
person.position.x = location.x
}
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
for touch in touches {
let location = touch.locationInNode(self)
person.position.x = location.x
}
}
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
}
}