code: def cursor_down(self, count=None):
          
          _top, bottom = self.margins or Margins(0, self.lines - 1)
          self.cursor.y = min(self.cursor.y + (count or 1), bottom)
docs: Move cursor down the indicated # of lines in same column.
          Cursor stops at bottom margin.
  
          :param int count: number of lines to skip.