Used by Variable/Connection.

https://github.com/apache/airflow/blob/894741e311ffd642e036b80d3b1b5d53c3747cad/airflow/secrets/metastore.py#L32

#
            
            
            
            
            
            
            
            _operator_link_class_path, data = next(iter(_operator_links_source.items()))
            if _operator_link_class_path in get_operator_extra_links():
                single_op_link_class = import_string(_operator_link_class_path)
            elif _operator_link_class_path in plugins_manager.registered_operator_link_classes:
                single_op_link_class = plugins_manager.registered_operator_link_classes[
                    _operator_link_class_path
                ]
            else:
                log.error("Operator Link class %r not registered", _operator_link_class_path)
                return {}
            op_predefined_extra_link: BaseOperatorLink = cattr.structure(data, single_op_link_class)
            op_predefined_extra_links.update({op_predefined_extra_link.name: op_predefined_extra_link})
        return op_predefined_extra_links
    @classmethod
    def _serialize_operator_extra_links(cls, operator_extra_links: Iterable[BaseOperatorLink]):