code: def do_plot(self, arg):
          
          usable, filename, append = self._redirect_split(arg)
          self.curargs["xscale"] = None
          self.curargs["yscale"] = None
          self._plot_generic(filename)
docs: Plots the current state of the shell's independent vs. dependent variables on the
          same set of axes. Give filename to save to as argument or leave blank to show.