code: def rows_above_layout(self):
          
          if self._in_alternate_screen:
              return 0
          elif self._min_available_height > 0:
              total_rows = self.output.get_size().rows
              last_screen_height = self._last_screen.height if self._last_screen else 0
              return total_rows - max(self._min_available_height, last_screen_height)
          else:
              raise HeightIsUnknownError('Rows above layout is unknown.')
docs: Return the number of rows visible in the terminal above the layout.