This is an easy and quick tip I came across while going through NSHipster's
Reader Submissions - 2016 [http://nshipster.com/new-years-2016/]. Sometimes we
use the blocks
[https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/ProgrammingWithObjectiveC/WorkingwithBlocks/WorkingwithBlocks.html]
which we may or may not be nil. Well, unlike