code: def _validate_config(strict=False):
      
      for index in settings.get_index_names():
          _validate_mapping(index, strict=strict)
          for model in settings.get_index_models(index):
              _validate_model(model)
      if settings.get_setting("update_strategy", "full") not in ["full", "partial"]:
          raise ImproperlyConfigured(
              "Invalid SEARCH_SETTINGS: 'update_strategy' value must be 'full' or 'partial'."
          )
docs: Validate settings.SEARCH_SETTINGS.