docs: def info():
      """this function will show only the 'box'-type
      attributes and their content in the cellpy.prms module"""
      print("convenience function for listing prms")
      print(type(prms))
      print(prms.__name__)
      print(f"prm file: {_get_prm_file()}")
  
      for key in prms.__dict__:
          if isinstance(prms.__dict__[key], box.Box):
              print()
              print(80 * "=")
              print(f"prms.{key}:")
              print(80 * "-")
              for subkey in prms.__dict__[key]:
                  print(
                      f"prms.{key}.{subkey} = ",
                      f"{prms.__dict__[key][subkey]}"
                  )
              print(80 * "=")