code: def set_smearing_function(self, function_name):
          
          if function_name == 'Cauchy':
              self._smearing_function = CauchyDistribution(self._sigma)
          else:
              self._smearing_function = NormalDistribution(self._sigma)
docs: function_name ==
          'Normal': smearing is done by normal distribution.
          'Cauchy': smearing is done by Cauchy distribution.