FRAME-OF
========

syntax: (frame-of <instance-specifier>
                  [:IDENTIFIER T | NIL | Var]
                  [:KB <kb-name>])

Warning: yet not implemented!

This function returns the object or the identifier
of a frame, which belongs to an instance. If you do 
not give any details, then ':IDENTIFIER' will be set 
to NIL and you will get the frame object.

example: >(frame-of Berlin)
         #<FRAME CAPITALCITY>
         
         >(frame-of Berlin :identifier T)
         CAPITALCITY