code: def _copy_from(self, rhs):
          
          self._manager = rhs._manager
          self._rlist = type(rhs._rlist)(rhs._rlist)
          self._region = rhs._region
          self._ofs = rhs._ofs
          self._size = rhs._size
  
          for region in self._rlist:
              region.increment_client_count()
  
          if self._region is not None:
              self._region.increment_client_count()
docs: Copy all data from rhs into this instance, handles usage count