Spritekit - Objective C - Add SKShapenodes to an array and then remove nodes one by one via button - ios

Question

Essentially I draw multiple lines on the screen by using a SKShapenode and adding it to a dictionary.
I want to now store the SKShapenodes in a array and remove the last item in the array via a button. Any idea anyone?
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch* touch = [touches anyObject];
CGPoint positionInScene = [touch locationInNode:self];
SKLabelNode *touchedNode = (SKLabelNode *)[self nodeAtPoint:positionInScene];
for (UITouch *touch in touches) {
CGPoint location = [touch locationInNode:self];
// Create a mutable path
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:location];
// Create a shape node using the path
lineNode = [SKShapeNode shapeNodeWithPath:path.CGPath];
lineNode.strokeColor = [SKColor blackColor];
lineNode.glowWidth = 3.0;
[_gameLineNode addChild:lineNode];
// Use touch pointer as the dictionary key. Since the dictionary key must conform to
// NSCopying, box the touch pointer in an NSValue
NSValue *key = [NSValue valueWithPointer:(void *)touch];
[lines setObject:lineNode forKey:key];
_lineNodeArray = [NSMutableArray array];
for (int i = 0; i < 10; i++) {
[_lineNodeArray addObject:lineNode];
}
}
}
- (void)touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event
{
for (UITouch *touch in touches) {
CGPoint location = [touch locationInNode:self];
// Retrieve the shape node that corresponds to touch
NSValue *key = [NSValue valueWithPointer:(void *)touch];
lineNode = [lines objectForKey:key];
if (lineNode != NULL) {
// Create and initial a mutable path with the lineNode's path
UIBezierPath *path = [UIBezierPath bezierPathWithCGPath:lineNode.path];
// Add a line to the current touch point
[path addLineToPoint:location];
// Update lineNode
lineNode.path = path.CGPath;
lineNode.physicsBody = [SKPhysicsBody bodyWithEdgeChainFromPath:path.CGPath];
lineNode.physicsBody.categoryBitMask = lineNodeCategory;
lineNode.physicsBody.contactTestBitMask = bubble1Category | bubble2Category| bubble3Category | bubble4Category | bubble5Category | bubble6Category;
lineNode.physicsBody.collisionBitMask = ballCategory | ballHalf1Category | ballHalf2Category;
lineNode.physicsBody.dynamic = YES;
lineNode.name = lineNodeCategoryName;
CGPoint _currentPoint = [[touches anyObject] locationInNode:self];
CGPoint _previousPoint = [[touches anyObject] previousLocationInNode:self];
_delta = CGPointMake(_currentPoint.x - _previousPoint.x, _currentPoint.y - _previousPoint.y);
}
}
}
Delete action - This will remove the line from the array but how do i remove the last line from the game view?
-(void)deleteLine{
_lineNodeArray = [NSMutableArray array];
[_lineNodeArray lastObject ];
[_lineNodeArray removeLastObject];
}