code: def attached_pane(self):
          
          for pane in self._panes:
              if 'pane_active' in pane:
                  # for now pane_active is a unicode
                  if pane.get('pane_active') == '1':
                      return Pane(window=self, **pane)
                  else:
                      continue
  
          return []
docs: Return the attached :class:`Pane`.
  
          Returns
          -------
          :class:`Pane`