code: def build_statusbar(self):
          
          if self.prompt_bar:
              logger.info("prompt is active, won't build status bar")
              return
          try:
              left_widgets = self.current_buffer.build_status_bar() or []
          except AttributeError:
              left_widgets = []
          text_list = []
          # FIXME: this code should be placed in buffer
          # TODO: display current active worker threads
          for idx, buffer in enumerate(self.buffers):
              #  #1 [I] fedora #2 [L]
              fmt = "#{idx} [{name}]"
              markup = fmt.format(idx=idx, name=buffer.display_name)
              text_list.append((
                  "status_box_focus" if buffer == self.current_buffer else "status_box",
                  markup,
              ))
              text_list.append(" ")
          text_list = text_list[:-1]
  
          if text_list:
              buffer_text = urwid.Text(text_list, align="right")
          else:
              buffer_text = urwid.Text("", align="right")
          columns = urwid.Columns(left_widgets + [buffer_text])
          return urwid.AttrMap(columns, "status")
docs: construct and return statusbar widget