Manually switching views in UIPageViewController causes exception - ios

Question

I have a UIPageViewController that displays two UIViewControllers and allows the user to swipe between the two. I implemented a button that allows the user to manually switch between the two. The code to execute this is as follows:
[self setViewControllers:#[[self.storyboard instantiateViewControllerWithIdentifier:#"PlayersViewController"]] direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:^(BOOL completion){}];
Unfortunately, every time I press the button, I get an exception that says:
* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '* -[__NSPlaceholderArray initWithObjects:count:]: attempt to insert nil object from objects[0]'
I call the method from my custom class that extends the UIPageViewControllerDelegate.
Any help would be much appreciated!
**Edit:
Here are relevant portions of my custom class:
- (void)viewDidLoad
{
[super viewDidLoad];
self.dataSource = self;
gvc = [[GamesViewController alloc] init];
pvc = [[PlayersViewController alloc] init];
[self setViewControllers:#[[self.storyboard instantiateViewControllerWithIdentifier:#"GamesViewController"]] direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];
}
- (void) slidepage
{
[self setViewControllers:#[[self.storyboard instantiateViewControllerWithIdentifier:#"PlayersViewController"]] direction:UIPageViewControllerNavigationDirectionReverse animated:NO completion:^(BOOL completion){NSLog(#"hihi");}];
}
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
{
if ([viewController isKindOfClass:[GamesViewController class]])
return nil;
return [self.storyboard instantiateViewControllerWithIdentifier:#"GamesViewController"];
}
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
if ([viewController isKindOfClass:[PlayersViewController class]])
return nil;
return [self.storyboard instantiateViewControllerWithIdentifier:#"PlayersViewController"];
}

Answer 1

It seems that
[self.storyboard instantiateViewControllerWithIdentifier:#"PlayersViewController"]
returns nil. This would mean that either self.storyboard is nil or the storyboard can't find a view controller for the given identifier.