update has already been overridden

Im getting a overridden error for my player and enemy. I made a enemy file and added this code into my gamescene. My enemy only spawns in if i delete my player movement code

func spawnEnemy() {      

let enemy = Enemy(image: SKSpriteNode(imageNamed: "enemy"))  

self.addChild(enemy)   }    

  override func update(_ currentTime: TimeInterval) {     spawnEnemy()   }