parents
(parents tag)
(parents h tag)
Answers the set of the immediate parents of tag in the hierarchy -- the global one, or h in
the two-argument form, nil when there are none. A class spelling is the keyword class
answers for it (see isa?), and a class adds its Java bases: the superclass and the
interfaces it implements. A host class object (interpreter and JVM) adds them as class objects,
like the oracle.