protected Collection against infinite recursion if incompletely init'd
protected Collection against infinite recursion if incompletely init'd

GenDataPro/pygr,RitwikGupta/pygr,ctb/pygr,GenDataPro/pygr,ctb/pygr,RitwikGupta/pygr,cjlee112/pygr,GenDataPro/pygr,ctb/pygr,theoryno3/pygr,theoryno3/pygr,theoryno3/pygr,cjlee112/pygr,RitwikGupta/pygr,ctb/pygr,cjlee112/pygr,ctb/pygr,cjlee112/pygr