message: use typing_extension instead
diff: @@ -30,17 +30,7 @@ import re
  import sys
  from collections import OrderedDict
  from datetime import date, timedelta
  -from typing import (
  - Any,
  - Callable,
  - Dict,
  - List,
  - Literal,
  - Optional,
  - Type,
  - TYPE_CHECKING,
  - Union,
  -)
  +from typing import Any, Callable, Dict, List, Optional, Type, TYPE_CHECKING, Union
  from cachelib.base import BaseCache
  from celery.schedules import crontab
  @@ -48,6 +38,7 @@ from dateutil import tz
  from flask import Blueprint
  from flask_appbuilder.security.manager import AUTH_DB
  from pandas.io.parsers import STR_NA_VALUES
  +from typing_extensions import Literal
  from werkzeug.local import LocalProxy
  from superset.jinja_context import BaseTemplateProcessor
  