The documentation you cite is out of date for iOS 7, which included numerous internal changes to Core Data's iCloud system. Among them is that when you call addPersistentStoreWithType:configuration:URL:options:error:
with iCloud keys in the options
dictionary, it internally calls URLForUbiquityContainerIdentifier:
for you. As a result, calling this method yourself isn't normally necessary if you're only using iCloud with Core Data.
If you're still supporting iOS 6 (not recommended if you're also using iCloud) then you'll need to call URLForUbiquityContainerIdentifier:
yourself.
For more details on Core Data + iCloud changes in iOS 7, I recommend WWDC 2013 session 207, "What's New in Core Data".