code: def meff_SO(self, **kwargs):
          '''
          Returns the split-off hole effective mass
          calculated from Eg_Gamma(T), Delta_SO, Ep and F.
          
          Interpolation of Eg_Gamma(T), Delta_SO, Ep and luttinger1, and
          then calculation of meff_SO is recommended for alloys.
          '''
          Eg = self.Eg_Gamma(**kwargs)
          Delta_SO = self.Delta_SO(**kwargs)
          Ep = self.Ep(**kwargs)
          luttinger1 = self.luttinger1(**kwargs)
          return 1./(luttinger1 - (Ep*Delta_SO)/(3*Eg*(Eg+Delta_SO))f meff_SO(self, **kwargs):
          '''
          Returns the split-off hole effective mass
          calculated from Eg_Gamma(T), Delta_SO, Ep and F.
          
          Interpolation of Eg_Gamma(T), Delta_SO, Ep and luttinger1, and
          then calculation of meff_SO is recommended for alloys.
          '''
          Eg = self.Eg_Gamma(**kwargs)
          Delta_SO = self.Delta_SO(**kwargs)
          Ep = self.Ep(**kwargs)
          luttinger1 = self.luttinger1(**kwargs)
          return 1./(luttinger1 - (Ep*Delta_SO)/(3*Eg*(Eg+Delta_SO)))
docs: Returns the split-off hole effective mass
          calculated from Eg_Gamma(T), Delta_SO, Ep and F.
          
          Interpolation of Eg_Gamma(T), Delta_SO, Ep and luttinger1, and
          then calculation of meff_SO is recommended for alloys.