The item at the specified index, if specified.
An array of the items in the collection, if the index is not specified
An object for silent failure, if the index is outside the bounds of the collection.
A dual purpose method to either return an array of all of the items in the collection, or return an item at the specified index (essentially forwards on to the WOOF_Collection::eq method).
The index of the item to retrieve. If this is not specified, an array of all of the items will be returned instead.