flask: Add types for cli_group argument to flask.Blueprint (#4011)

* Add types for cli_group argument to flask.Blueprint

* Use private _Sentinel type for default argument to Blueprint cli_group

Author: razzius

third_party/2and3/flask/blueprints.pyi

@@ -9,6 +9,8 @@ from typing import Any, Callable, Optional, Type, TypeVar, Union
 _T = TypeVar('_T')
 _VT = TypeVar('_VT', bound=_ViewFunc)
 
+class _Sentinel(object): ...
+
 class BlueprintSetupState:
     app: Any = ...
     blueprint: Any = ...
@@ -34,7 +36,8 @@ class Blueprint(_PackageBoundObject):
     static_url_path: Optional[str] = ...
     deferred_functions: Any = ...
     url_values_defaults: Any = ...
-    def __init__(self, name: str, import_name: str, static_folder: Optional[str] = ..., static_url_path: Optional[str] = ..., template_folder: Optional[str] = ..., url_prefix: Optional[str] = ..., subdomain: Optional[str] = ..., url_defaults: Optional[Any] = ..., root_path: Optional[str] = ...) -> None: ...
+    cli_group: Union[Optional[str], _Sentinel] = ...
+    def __init__(self, name: str, import_name: str, static_folder: Optional[str] = ..., static_url_path: Optional[str] = ..., template_folder: Optional[str] = ..., url_prefix: Optional[str] = ..., subdomain: Optional[str] = ..., url_defaults: Optional[Any] = ..., root_path: Optional[str] = ..., cli_group: Union[Optional[str], _Sentinel] = ...) -> None: ...
     def record(self, func: Any) -> None: ...
     def record_once(self, func: Any): ...
     def make_setup_state(self, app: Any, options: Any, first_registration: bool = ...): ...