From e815c803a6f9659df025c38d79d28db396861ebc Mon Sep 17 00:00:00 2001
From: speezepearson <speezepearson@users.noreply.github.com>
Date: Wed, 13 Jul 2016 06:16:37 -0700
Subject: [PATCH] add ChainMap class to collections module (#361)

* add ChainMap class to collections module

* ...and add it for Python 2 as well.
---
 stdlib/2.7/collections.pyi        | 14 ++++++++++++++
 stdlib/3/collections/__init__.pyi | 14 ++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/stdlib/2.7/collections.pyi b/stdlib/2.7/collections.pyi
index 9b6bc4d07..9d4624301 100644
--- a/stdlib/2.7/collections.pyi
+++ b/stdlib/2.7/collections.pyi
@@ -90,3 +90,17 @@ class defaultdict(Dict[_KT, _VT], Generic[_KT, _VT]):
     def __init__(self, default_factory: Callable[[], _VT],
                  iterable: Iterable[Tuple[_KT, _VT]]) -> None: ...
     def __missing__(self, key: _KT) -> _VT: ...
+
+class ChainMap(Dict[_KT, _VT], Generic[_KT, _VT]):
+    @overload
+    def __init__(self) -> None: ...
+    @overload
+    def __init__(self, *maps: Mapping[_KT, _VT]) -> None: ...
+
+    @property
+    def maps(self) -> List[Mapping[_KT, _VT]]: ...
+
+    def new_child(self, m: Mapping[_KT, _VT] = ...) -> ChainMap[_KT, _VT]: ...
+
+    @property
+    def parents(self) -> ChainMap[_KT, _VT]: ...
diff --git a/stdlib/3/collections/__init__.pyi b/stdlib/3/collections/__init__.pyi
index cb3215101..6e741006f 100644
--- a/stdlib/3/collections/__init__.pyi
+++ b/stdlib/3/collections/__init__.pyi
@@ -133,3 +133,17 @@ class defaultdict(Dict[_KT, _VT], Generic[_KT, _VT]):
 
     def __missing__(self, key: _KT) -> _VT: ...
     # TODO __reversed__
+
+class ChainMap(Dict[_KT, _VT], Generic[_KT, _VT]):
+    @overload
+    def __init__(self) -> None: ...
+    @overload
+    def __init__(self, *maps: Mapping[_KT, _VT]) -> None: ...
+
+    @property
+    def maps(self) -> List[Mapping[_KT, _VT]]: ...
+
+    def new_child(self, m: Mapping[_KT, _VT] = ...) -> ChainMap[_KT, _VT]: ...
+
+    @property
+    def parents(self) -> ChainMap[_KT, _VT]: ...