Answer true iff this TripleBunch contains a triple with .sameValueAs
subject, predicate, and object. (Typically this only matters for the
object. For example, integer literals with different numbers of leading
zeroes can be .sameValueAs but not .equals).
Remove the object key from this hash's keys if it
is present (if it's absent, do nothing). If a key is removed, the
removeAssociatedValues will be invoked. If a key
is moved, the moveAssociatedValues method will
be called.
Answer an iterator over all the triples in this bunch. If use of .remove on
this iterator empties the bunch, the emptied method of
container is invoked.