docs: def export_to_directory_crtomo(self, directory, norrec='norrec'):
          """Export the sEIT data into data files that can be read by CRTomo.
  
          Parameters
          ----------
          directory : string
              output directory. will be created if required
          norrec : string (nor|rec|norrec)
              Which data to export. Default: norrec
  
          """
          exporter_crtomo.write_files_to_directory(
              self.data, directory, norrec=norrec
          )