first version finished

django/utils/regex_helper.pyi

@@ -0,0 +1,28 @@
+from typing import (
+    Any,
+    Iterator,
+    List,
+    Tuple,
+    Type,
+    Union,
+)
+
+
+def contains(
+    source: Union[str, Group, NonCapture],
+    inst: Type[Group]
+) -> bool: ...
+
+
+def flatten_result(source: Any) -> Union[Tuple[List[str], List[List[str]]], Tuple[List[str], List[List[Any]]]]: ...
+
+
+def get_quantifier(ch: str, input_iter: Iterator[Any]) -> Union[Tuple[int, None], Tuple[int, str]]: ...
+
+
+def normalize(
+    pattern: str
+) -> Union[List[Tuple[str, List[Any]]], List[Union[Tuple[str, List[Any]], Tuple[str, List[str]]]], List[Tuple[str, List[str]]]]: ...
+
+
+def walk_to_end(ch: str, input_iter: Iterator[Any]) -> None: ...