From c0d0f7fe14c280df477509e4939359919b885b3d Mon Sep 17 00:00:00 2001
From: Tim Abbott <tabbott@dropbox.com>
Date: Fri, 22 Jan 2016 17:42:45 -0800
Subject: [PATCH] Fix os.environ improperly classified as not mutable for
 python 2.

In Python, you can change the environment by writing to os.environ.

This seems to already be handled correctly in the python 3 type data,
so we just need to fix it for 2.7.
---
 stdlib/2.7/__builtin__.pyi | 1 +
 stdlib/2.7/os/__init__.pyi | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/stdlib/2.7/__builtin__.pyi b/stdlib/2.7/__builtin__.pyi
index 9c59ed922..7f4d6e47d 100644
--- a/stdlib/2.7/__builtin__.pyi
+++ b/stdlib/2.7/__builtin__.pyi
@@ -824,3 +824,4 @@ def cmp(x: Any, y: Any) -> int: ...
 def execfile(filename: str, globals: Dict[str, Any] = None, locals: Dict[str, Any] = None) -> None: ...
 
 class file(BinaryIO): ...
+
diff --git a/stdlib/2.7/os/__init__.pyi b/stdlib/2.7/os/__init__.pyi
index 18a6fa0a3..73907d6bf 100644
--- a/stdlib/2.7/os/__init__.pyi
+++ b/stdlib/2.7/os/__init__.pyi
@@ -1,11 +1,11 @@
 # created from https://docs.python.org/2/library/os.html
 
-from typing import List, Tuple, Union, Sequence, Mapping, IO, Any, Optional, AnyStr
+from typing import List, Tuple, Union, Sequence, Mapping, IO, Any, Optional, AnyStr, MutableMapping
 import os.path as path
 
 error = OSError
 name = ... # type: str
-environ = ... # type: Mapping[str, str]
+environ = ... # type: MutableMapping[str, str]
 
 def chdir(path: unicode) -> None: ...
 def fchdir(fd: int) -> None: ...