code: def enable_external_loaders(obj):
      
      for name, loader in ct.EXTERNAL_LOADERS.items():
          enabled = getattr(
              obj, "{}_ENABLED_FOR_DYNACONF".format(name.upper()), False
          )
          if (
              enabled
              and enabled not in false_values
              and loader not in obj.LOADERS_FOR_DYNACONF
          ):  # noqa
              obj.logger.debug("loaders: Enabling %s", loader)
              obj.LOADERS_FOR_DYNACONF.insert(0, loader)
docs: Enable external service loaders like `VAULT_` and `REDIS_`
      looks forenv variables like `REDIS_ENABLED_FOR_DYNACONF`