我有这个代码，我连接两个节点，一切都按预期工作。问题是我想删除节点之间的连接蓝线（附图为参考）。我该怎么做？
//This function creates a player sprite node and place it on screen
func addPlayer () {
player = SKShapeNode(circleOfRadius: 30)
player.position = CGPoint(x: playableArea.midX, y: playableArea.midY - 600)
player.fillColor = UIColor.black
player.strokeColor = UIColor.white
player.lineWidth = 4
player.physicsBody = SKPhysicsBody(circleOfRadius: 30)
player.physicsBody?.affectedByGravity = false
player.physicsBody?.isDynamic = false
player.name = "characterColor"
addChild(player)
}
//This function creates second node and attach it as tail of player node and also joint player and tail node
func addTail () {
tail = SKShapeNode(circleOfRadius: 25)
tail.position = CGPoint(x: player.position.x, y: player.position.y - 60)
tail.physicsBody = SKPhysicsBody(circleOfRadius: 25)
tail.fillColor = UIColor.black
addChild(tail)
let joint = SKPhysicsJointPin.joint(withBodyA: player!.physicsBody!, bodyB: tail.physicsBody!, anchor: player.position)
joint.shouldEnableLimits = true
joint.lowerAngleLimit = 0
joint.upperAngleLimit = 0
joint.frictionTorque = 0.1
physicsWorld.add(joint)
}
