Consistently use '= ...' for optional parameters.

stdlib/3/multiprocessing/__init__.pyi

@@ -6,7 +6,7 @@ class Lock(): ...
 class Process(): ...
 
 class Queue():
-    def get(block: bool = None, timeout: float = None) -> Any: ...
+    def get(block: bool = ..., timeout: float = ...) -> Any: ...
 
 class Value():
-    def __init__(typecode_or_type: str, *args: Any, lock: bool = True) -> None: ...
+    def __init__(typecode_or_type: str, *args: Any, lock: bool = ...) -> None: ...

stdlib/3/multiprocessing/managers.pyi

@@ -5,4 +5,4 @@
 from typing import Any
 
 class BaseManager():
-    def register(typeid: str, callable: Any = None) -> None: ...
+    def register(typeid: str, callable: Any = ...) -> None: ...

stdlib/3/multiprocessing/pool.pyi

@@ -3,4 +3,4 @@
 # NOTE: These are incomplete!
 
 class ThreadPool():
-    def __init__(self, processes: int = None) -> None: ...
+    def __init__(self, processes: int = ...) -> None: ...