Add type stubs for multiprocessing.Manager() (#1270)

* Use Dict/List types and _Namespace alias

* Use TypeVar definitions for mapping/sequence stubs

stdlib/3/multiprocessing/__init__.pyi

@@ -3,6 +3,7 @@
 from typing import Any, Callable, Iterable, Mapping, Optional, Dict, List
 
 from multiprocessing.context import BaseContext
+from multiprocessing.managers import SyncManager
 from multiprocessing.process import current_process as current_process
 
 class Lock():
@@ -105,3 +106,4 @@ class Value():
 # ----- multiprocessing function stubs -----
 def cpu_count() -> int: ...
 def freeze_support() -> None: ...
+def Manager() -> SyncManager: ...

stdlib/3/multiprocessing/managers.pyi

@@ -2,9 +2,33 @@
 
 # NOTE: These are incomplete!
 
-from typing import Any
+import queue
+import threading
+from typing import Any, Dict, List, Mapping, Sequence, TypeVar
+
+_T = TypeVar('_T')
+_KT = TypeVar('_KT')
+_VT = TypeVar('_VT')
+
+class Namespace: ...
+
+_Namespace = Namespace
 
 class BaseManager:
     def register(self, typeid: str, callable: Any = ...) -> None: ...
 
+class SyncManager(BaseManager):
+    def BoundedSemaphore(self, value: Any = ...) -> threading.BoundedSemaphore: ...
+    def Condition(self, lock: Any = ...) -> threading.Condition: ...
+    def Event(self) -> threading.Event: ...
+    def Lock(self) -> threading.Lock: ...
+    def Namespace(self) -> _Namespace: ...
+    def Queue(self, maxsize: int = ...) -> queue.Queue: ...
+    def RLock(self) -> threading.RLock: ...
+    def Semaphore(self, value: Any = ...) -> threading.Semaphore: ...
+    def Array(self, typecode: Any, sequence: Sequence[_T]) -> Sequence[_T]: ...
+    def Value(self, typecode: Any, value: _T) -> _T: ...
+    def dict(self, sequence: Mapping[_KT, _VT] = ...) -> Dict[_KT, _VT]: ...
+    def list(self, sequence: Sequence[_T] = ...) -> List[_T]: ...
+
 class RemoteError(Exception): ...