Show the plot using matplotlib.

        Args:
            xlim: Specifies the x-axis limits. Set to None for automatic
                determination.
            ylim: Specifies the y-axis limits.
            units: units for the frequencies. Accepted values thz, ev, mev, ha, cm-1, cm^-1.

def show(self, xlim=None, ylim=None, units="thz"):
        """
        Show the plot using matplotlib.

        Args:
            xlim: Specifies the x-axis limits. Set to None for automatic
                determination.
            ylim: Specifies the y-axis limits.
            units: units for the frequencies. Accepted values thz, ev, mev, ha, cm-1, cm^-1.
        """
        plt = self.get_plot(xlim, ylim, units=units)
        plt.show()