code: def get_deep_focus(self, startfrom=None):
          
          if not startfrom:
              startfrom = self.current_buffer
          if 'get_focus' in dir(startfrom):
              focus = startfrom.get_focus()
              if isinstance(focus, tuple):
                  focus = focus[0]
              if isinstance(focus, urwid.Widget):
                  return self.get_deep_focus(startfrom=focus)
          return startfrom
docs: return the bottom most focussed widget of the widget tree