[refactor] Centralizing custom Python types (#9026)

superset/typing.py

@@ -14,9 +14,10 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
-from typing import Any, Callable, Dict, Union
+from typing import Any, Callable, Dict, List, Optional, Union
 
 from flask import Flask
 from flask_caching import Cache
 
 CacheConfig = Union[Callable[[Flask], Cache], Dict[str, Any]]
+VizData = Optional[Union[List[Any], Dict[Any, Any]]]

superset/viz.py

@@ -32,7 +32,7 @@ from collections import defaultdict, OrderedDict
 from datetime import datetime, timedelta
 from functools import reduce
 from itertools import product
-from typing import Any, Dict, List, Optional, Set, Tuple, TYPE_CHECKING, Union
+from typing import Any, Dict, List, Optional, Set, Tuple, TYPE_CHECKING
 
 import geohash
 import numpy as np
@@ -50,6 +50,7 @@ from superset import app, cache, get_css_manifest_files
 from superset.constants import NULL_STRING
 from superset.exceptions import NullValueException, SpatialException
 from superset.models.helpers import QueryResult
+from superset.typing import VizData
 from superset.utils import core as utils
 from superset.utils.core import (
     DTTM_ALIAS,
@@ -77,8 +78,6 @@ METRIC_KEYS = [
     "size",
 ]
 
-VizData = Optional[Union[List[Any], Dict[Any, Any]]]
-
 
 class BaseViz: