def classic_administrators(self):
        """Instance depends on the API version:

           * 2015-06-01: :class:`ClassicAdministratorsOperations<azure.mgmt.authorization.v2015_06_01.operations.ClassicAdministratorsOperations>`
        """
        api_version = self._get_api_version('classic_administrators')
        if api_version == '2015-06-01':
            from .v2015_06_01.operations import ClassicAdministratorsOperations as OperationClass
        else:
            raise NotImplementedError("APIVersion {} is not available".format(api_version))
        return OperationClass(self._client, self.config, Serializer(self._models_dict(api_version)), Deserializer(self._models_dict(api_version)))