diff --git a/Doc/lib/libos.tex b/Doc/lib/libos.tex
index 0fb8f10..e9302d1 100644
--- a/Doc/lib/libos.tex
+++ b/Doc/lib/libos.tex
@@ -706,8 +706,9 @@
 Set the access and modified times of the file specified by \var{path}.
 If \var{times} is \code{None}, then the file's access and modified
 times are set to the current time.  Otherwise, \var{times} must be a
-2-tuple of numbers, of the form \var{(atime, mtime)} which is used to
-set the access and modified times, respectively.
+2-tuple of numbers, of the form \code{(\var{atime}, \var{mtime})}
+which is used to set the access and modified times, respectively.
+\versionchanged[added support for \code{None} for \var{times}]{1.6}
 Availability: Macintosh, \UNIX{}, Windows.
 \end{funcdesc}