docs: def is_tomodir(subdirectories):
      """provided with the subdirectories of a given directory, check if this is
      a tomodir
      """
      required = (
          'exe',
          'config',
          'rho',
          'mod',
          'inv'
      )
      is_tomodir = True
      for subdir in required:
          if subdir not in subdirectories:
              is_tomodir = False
      return is_tomodir