._id2ref	ObjectSpace._id2ref
.add_finalizer	ObjectSpace.add_finalizer
.call_finalizer	ObjectSpace.call_finalizer
.define_finalizer	ObjectSpace.define_finalizer
.each_object	ObjectSpace.each_object
.finalizers	ObjectSpace.finalizers
.garbage_collect	ObjectSpace.garbage_collect
.remove_finalizer	ObjectSpace.remove_finalizer
.undefine_finalizer	ObjectSpace.undefine_finalizer
