code: def get_conductivity(self, output='eigs', doping_levels=True,
                           relaxation_time=1e-14):
          
          return BoltztrapAnalyzer._format_to_output(self._cond,
                                                     self._cond_doping, output,
                                                     doping_levels,
                                                     relaxation_time)
docs: Gives the conductivity (1/Ohm*m) in either a full 3x3 tensor
              form, as 3 eigenvalues, or as the average value
              (trace/3.0) If doping_levels=True, the results are given at
              different p and n doping
              levels (given by self.doping), otherwise it is given as a series
              of electron chemical potential values
  
              Args:
                  output (string): the type of output. 'tensor' give the full
                  3x3 tensor, 'eigs' its 3 eigenvalues and
                  'average' the average of the three eigenvalues
                  doping_levels (boolean): True for the results to be given at
                  different doping levels, False for results
                  at different electron chemical potentials
                  relaxation_time (float): constant relaxation time in secs
  
              Returns:
                  If doping_levels=True, a dictionary {temp:{'p':[],'n':[]}}.
                  The 'p' links to conductivity
                  at p-type doping and 'n' to the conductivity at n-type
                  doping. Otherwise,
                  returns a {temp:[]} dictionary. The result contains either
                  the sorted three eigenvalues of the symmetric
                  conductivity tensor (format='eigs') or a full tensor (3x3
                  array) (output='tensor') or as an average
                  (output='average').
                  The result includes a given constant relaxation time
  
                  units are 1/Ohm*m