You want to add pod 'NSError+LocolizedDescription', '~> 0.0'
similar to the following to your Podfile:
target 'MyApp' do
pod 'NSError+LocolizedDescription', '~> 0.0'
end
Then run a pod install
inside your terminal, or from CocoaPods.app.
Alternatively to give it a test run, run the command:
pod try NSError+LocolizedDescription