diff --git a/Doc/library/os.path.rst b/Doc/library/os.path.rst
index 8e7ee8b..a673b81 100644
--- a/Doc/library/os.path.rst
+++ b/Doc/library/os.path.rst
@@ -87,9 +87,10 @@
 .. function:: commonpath(paths)
 
    Return the longest common sub-path of each pathname in the sequence
-   *paths*.  Raise :exc:`ValueError` if *paths* contains both absolute and relative
-   pathnames, or if *paths* is empty.  Unlike :func:`commonprefix`, this
-   returns a valid path.
+   *paths*.  Raise :exc:`ValueError` if *paths* contain both absolute
+   and relative pathnames, the *paths* are on the different drives or
+   if *paths* is empty.  Unlike :func:`commonprefix`, this returns a
+   valid path.
 
    .. availability:: Unix, Windows.