Protected_checkProtected_moveProtected_removeReturns an item identified by the unique constraint key. Returns null, if there is no uniqueness constraint.
the value to test against. does a shallow comparison, if the passed a non-atomic value
StaticfromCreates a Collection from an iterable, such as an Array.
Get the symbol which is attached to an item prior to its removal. If an item is removed, the current index of the item is set on the item with this symbol.