code: def do_down(self, arg):
          
          if self.curindex + 1 == len(self.stack):
              self.error('Newest frame')
              return
          try:
              count = int(arg or 1)
          except ValueError:
              self.error('Invalid frame count (%s)' % arg)
              return
          if count < 0:
              newframe = len(self.stack) - 1
          else:
              newframe = min(len(self.stack) - 1, self.curindex + count)
          self._select_frame(newframe)
docs: d(own) [count]
          Move the current frame count (default one) levels down in the
          stack trace (to a newer frame).