refactor(api): tighten phase 1 shared type contracts (#33453)

api/libs/module_loading.py

@@ -7,9 +7,10 @@ https://github.com/django/django/blob/main/django/utils/module_loading.py
 
 import sys
 from importlib import import_module
+from typing import Any
 
 
-def cached_import(module_path: str, class_name: str):
+def cached_import(module_path: str, class_name: str) -> Any:
     """
     Import a module and return the named attribute/class from it, with caching.
 
@@ -20,16 +21,14 @@ def cached_import(module_path: str, class_name: str):
     Returns:
         The imported attribute/class
     """
-    if not (
-        (module := sys.modules.get(module_path))
-        and (spec := getattr(module, "__spec__", None))
-        and getattr(spec, "_initializing", False) is False
-    ):
+    module = sys.modules.get(module_path)
+    spec = getattr(module, "__spec__", None) if module is not None else None
+    if module is None or getattr(spec, "_initializing", False):
         module = import_module(module_path)
     return getattr(module, class_name)
 
 
-def import_string(dotted_path: str):
+def import_string(dotted_path: str) -> Any:
     """
     Import a dotted module path and return the attribute/class designated by
     the last name in the path. Raise ImportError if the import failed.