code: def __load_omitted_parcov(self):
          
          if self.omitted_parcov_arg is None and self.omitted_par_arg is None:
              raise Exception("ErrVar.__load_omitted_parcov: " +
                              "both omitted args are None")
          # try to set omitted_parcov by extracting from base parcov
          if self.omitted_parcov_arg is None and self.omitted_par_arg is not None:
              # check to see if omitted par names are in parcov
              found = True
              for par_name in self.omitted_jco.col_names:
                  if par_name not in self.parcov.col_names:
                      found = False
                      break
              if found:
                  # need to access attribute directly, not view of attribute
                  self.__omitted_parcov = \
                      self._LinearAnalysis__parcov.extract(
                          row_names=self.omitted_jco.col_names)
              else:
                  self.logger.warn("ErrVar.__load_omitted_parun: " +
                                   "no omitted parcov arg passed: " +
                          "setting omitted parcov as identity Matrix")
                  self.__omitted_parcov = Cov(
                      x=np.ones(self.omitted_jco.shape[1]),
                      names=self.omitted_jco.col_names, isdiagonal=True)
          elif self.omitted_parcov_arg is not None:
              raise NotImplementedError()
docs: private: set the omitted_parcov attribute