code: public final TypeV get( long key ) {
      if( key == NO_KEY ) {
        final Object V = _val_1;
        return V == TOMBSTONE ? null : (TypeV)V;
      }
      final Object V = _chm.get_impl(key);
      assert !(V instanceof Prime); // Never return a Prime
      assert V != TOMBSTONE;
      return (TypeV)V;
    }
docs: Never returns a Prime nor a Tombstone.