Feature added by Bill van Melle: when no timezone is present, assume
local time -- that's better than failure.
diff --git a/Doc/librfc822.tex b/Doc/librfc822.tex
index aa7e459..d764ce6 100644
--- a/Doc/librfc822.tex
+++ b/Doc/librfc822.tex
@@ -47,11 +47,13 @@
 for Greenwich Mean Time).  (Note that the sign of the timezone offset
 is the opposite of the sign of the \code{time.timezone} variable for
 the same timezone; the latter variable follows the \POSIX{} standard
-while this module follows \rfc{822}.)
+while this module follows \rfc{822}.)  If the input string has no
+timezone, the last element of the tuple returned is \code{None}.
 \end{funcdesc}
 
 \begin{funcdesc}{mktime_tz}{tuple}
 Turn a 10-tuple as returned by \code{parsedate_tz()} into a UTC timestamp.
+It the timezone item in the tuple is \code{None}, assume local time.
 Minor deficiency: this first interprets the first 8 elements as a
 local time and then compensates for the timezone difference;
 this may yield a slight error around daylight savings time