Used by Variable/Connection.

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

self._operator_name = operator_name
    @classmethod
    def serialize_mapped_operator(cls, op: MappedOperator) -> dict[str, Any]:
        serialized_op = cls._serialize_node(op, include_deps=op.deps != MappedOperator.deps_for(BaseOperator))
        
        expansion_kwargs = op._get_specified_expand_input()
        if TYPE_CHECKING:  
            _ExpandInputRef.validate_expand_input_value(expansion_kwargs.value)
        serialized_op[op._expand_input_attr] = {
            "type": get_map_type_key(expansion_kwargs),
            "value": cls.serialize(expansion_kwargs.value),
        }
        
        
        serialized_partial = serialized_op["partial_kwargs"]
        for k, default in _get_default_mapped_partial().items():
            try:
                v = serialized_partial[k]
            except KeyError:
                continue
            if v == default:
                del serialized_partial[k]
        serialized_op["_is_mapped"] = True
        return serialized_op
    @classmethod
    def serialize_operator(cls, op: BaseOperator) -> dict[str, Any]: