diff --git a/stdlib/2.7/os/__init__.pyi b/stdlib/2.7/os/__init__.pyi
index da49f10f1..7b754b764 100644
--- a/stdlib/2.7/os/__init__.pyi
+++ b/stdlib/2.7/os/__init__.pyi
@@ -1,6 +1,6 @@
 # created from https://docs.python.org/2/library/os.html
 
-from typing import List, Tuple, Union, Sequence, Mapping, IO, Any, Optional, AnyStr, MutableMapping
+from typing import List, Tuple, Union, Sequence, Mapping, IO, Any, Optional, AnyStr, MutableMapping, Iterator
 import os.path as path
 
 error = OSError
@@ -134,7 +134,10 @@ def rmdir(path: unicode) -> None: ...
 # TODO(MichalPokorny)
 def stat(path: unicode) -> Any: ...
 
-# TODO: stat_float_times, statvfs, tempnam, tmpnam, TMP_MAX, walk
+# TODO: stat_float_times, statvfs, tempnam, tmpnam, TMP_MAX
+def walk(top: AnyStr, topdown: bool = ..., onerror: Any = ...,
+         followlinks: bool = ...) -> Iterator[Tuple[AnyStr, List[AnyStr],
+                                                    List[AnyStr]]]: ...
 
 def symlink(source: unicode, link_name: unicode) -> None: ...
 def unlink(path: unicode) -> None: ...
diff --git a/stdlib/3/os/__init__.pyi b/stdlib/3/os/__init__.pyi
index 71e7cff85..dbdc9661a 100644
--- a/stdlib/3/os/__init__.pyi
+++ b/stdlib/3/os/__init__.pyi
@@ -267,13 +267,7 @@ def utime(path: AnyStr, times: Union[Tuple[int, int], Tuple[float, float]] = ...
 # TODO onerror: function from OSError to void
 def walk(top: AnyStr, topdown: bool = ..., onerror: Any = ...,
          followlinks: bool = ...) -> Iterator[Tuple[AnyStr, List[AnyStr],
-                                                      List[AnyStr]]]: ...
-# walk(): "By default errors from the os.listdir() call are ignored.  If
-# optional arg 'onerror' is specified, it should be a function; it
-# will be called with one argument, an os.error instance.  It can
-# report the error to continue with the walk, or raise the exception
-# to abort the walk.  Note that the filename is available as the
-# filename attribute of the exception object."
+                                                    List[AnyStr]]]: ...
 
 def abort() -> 'None': ...
 def execl(path: AnyStr, arg0: AnyStr, *args: AnyStr) -> None: ...