||An Acceptor is an object that is able to "add" objects to itself.
||An extension of Accepter and Remover, describing an object that can keep
references to objects (via add() and remove(), and then check to see if they
are currently held, determine how many objects are contained, and remove all
objects at once.
|KeyedContainer<T extends Referenced>
||KeyedContainer adds functionality to Container to support "keying" Referenced
objects with their references - i.e., it's possible to access, add, or remove
objects in the list by their associated String.
||A Remover is a general-purpose interface for "removing" objects.