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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 plot_entropy(self, tmin, tmax, ntemp, ylim=None, **kwargs):
 """ Plots the vibrational entrpy in a temperature range. Args: tmin: minimum temperature tmax: maximum temperature ntemp: number of steps ylim: tuple specifying the y-axis limits. kwargs: kwargs passed to the matplotlib function 'plot'. Returns: matplotlib figure """

        temperatures = np.linspace(tmin, tmax, ntemp)

        if self.structure:
            ylabel = r"$S$ (J/K/mol)"
        else:
            ylabel = r"$S$ (J/K/mol-c)"

        fig = self._plot_thermo(self.dos.entropy, temperatures, ylabel=ylabel, ylim=ylim, **kwargs)

        return fig