docs: def import_crtomo(self, directory, frequency_file='frequencies.dat',
                        data_prefix='volt_', **kwargs):
          """CRTomo importer"""
  
          # we get not electrode positions (dummy1) and no topography data
          # (dummy2)
          df, dummy1, dumm2 = reda_crtomo_exporter.load_seit_data(
              directory, frequency_file, data_prefix, **kwargs)
          self._add_to_container(df)
  
          print('Summary:')
          self._describe_data(df)