
**Apache Airflow version**:

master

**What happened**:

https://github.com/apache/airflow/blob/master/airflow/models/baseoperator.py#L356 --> should be timedelta not datetime


airflow/serialization/serialized_objects.py
#
#
"""Serialized DAG and BaseOperator"""
import datetime
import enum
import logging
from inspect import Parameter, signature
from typing import TYPE_CHECKING, Any, Dict, Iterable, List, Optional, Set, Union
import cattr
import pendulum
from dateutil import relativedelta
try:
    from functools import cache
except ImportError:
    from functools import lru_cache
    cache = lru_cache(maxsize=None)
from pendulum.tz.timezone import Timezone
from airflow.exceptions import AirflowException, SerializationError
from airflow.models.baseoperator import BaseOperator, BaseOperatorLink
from airflow.models.connection import Connection
from airflow.models.dag import DAG
from airflow.providers_manager import ProvidersManager
from airflow.serialization.enums import DagAttributeTypes as DAT, Encoding
from airflow.serialization.helpers import serialize_template_field
from airflow.serialization.json_schema import Validator, load_dag_schema
from airflow.settings import json
from airflow.utils.code_utils import get_python_source