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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 total_surface_energy(self):
 """ Total surface energy of the Wulff shape. Returns: (float) sum(surface_energy_hkl * area_hkl) """

        tot_surface_energy = 0
        for hkl in self.miller_energy_dict.keys():
            tot_surface_energy += self.miller_energy_dict[hkl] * \
                                  self.miller_area_dict[hkl]
        return tot_surface_energy