docs: def is_valid_group(group_name, nova_creds):
      """
      Checks to see if the configuration file contains a SUPERNOVA_GROUP
      configuration option.
      """
      valid_groups = []
      for key, value in nova_creds.items():
          supernova_groups = value.get('SUPERNOVA_GROUP', [])
          if hasattr(supernova_groups, 'startswith'):
              supernova_groups = [supernova_groups]
          valid_groups.extend(supernova_groups)
      valid_groups.append('all')
      if group_name in valid_groups:
          return True
      else:
          return False