code: def _unpickle_panel_compat(self, state):  # pragma: no cover
          
          from pandas.io.pickle import _unpickle_array
  
          _unpickle = _unpickle_array
          vals, items, major, minor = state
  
          items = _unpickle(items)
          major = _unpickle(major)
          minor = _unpickle(minor)
          values = _unpickle(vals)
          wp = Panel(values, items, major, minor)
          self._data = wp._data
docs: Unpickle the panel.