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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def do_plot(self, arg):
 """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. """

        usable, filename, append = self._redirect_split(arg)
        self.curargs["xscale"] = None
        self.curargs["yscale"] = None
        self._plot_generic(filename)