Sessions has() vs exists() vs missing()

Do you know about has, exists and missing methods in Laravel session?

1// The has method returns true if the item is present & not null.
2$request->session()->has('key');
3 
4// THe exists method returns true if the item ir present, event if its value is null
5$request->session()->exists('key');
6 
7// THe missing method returns true if the item is not present or if the item is null
8$request->session()->missing('key');

Tip given by @iamharis010