Plot the Seebeck coefficient in function of temperature for different 
        doping levels.

        Args:
            dopings: the default 'all' plots all the doping levels in the analyzer.
                     Specify a list of doping levels if you want to plot only some.
            output: with 'average' you get an average of the three directions
                    with 'eigs' you get all the three directions.
        Returns:
            a matplotlib object

def plot_seebeck_temp(self, doping='all', output='average'):
        """
        Plot the Seebeck coefficient in function of temperature for different 
        doping levels.

        Args:
            dopings: the default 'all' plots all the doping levels in the analyzer.
                     Specify a list of doping levels if you want to plot only some.
            output: with 'average' you get an average of the three directions
                    with 'eigs' you get all the three directions.
        Returns:
            a matplotlib object
        """

        import matplotlib.pyplot as plt
        if output == 'average':
            sbk = self._bz.get_seebeck(output='average')
        elif output == 'eigs':
            sbk = self._bz.get_seebeck(output='eigs')

        plt.figure(figsize=(22, 14))
        tlist = sorted(sbk['n'].keys())
        doping = self._bz.doping['n'] if doping == 'all' else doping
        for i, dt in enumerate(['n', 'p']):
            plt.subplot(121 + i)
            for dop in doping:
                d = self._bz.doping[dt].index(dop)
                sbk_temp = []
                for temp in tlist:
                    sbk_temp.append(sbk[dt][temp][d])
                if output == 'average':
                    plt.plot(tlist, sbk_temp, marker='s',
                             label=str(dop) + ' $cm^{-3}$')
                elif output == 'eigs':
                    for xyz in range(3):
                        plt.plot(tlist, zip(*sbk_temp)[xyz], marker='s',
                                 label=str(xyz) + ' ' + str(dop) + ' $cm^{-3}$')
            plt.title(dt + '-type', fontsize=20)
            if i == 0:
                plt.ylabel("Seebeck \n coefficient  ($\\mu$V/K)", fontsize=30.0)
            plt.xlabel('Temperature (K)', fontsize=30.0)

            p = 'lower right' if i == 0 else ''
            plt.legend(loc=p, fontsize=15)
            plt.grid()
            plt.xticks(fontsize=25)
            plt.yticks(fontsize=25)

        plt.tight_layout()

        return plt