diff --git a/Doc/library/imaplib.rst b/Doc/library/imaplib.rst
index dc94beb..632baa3 100644
--- a/Doc/library/imaplib.rst
+++ b/Doc/library/imaplib.rst
@@ -85,9 +85,9 @@
 
 .. function:: Internaldate2tuple(datestr)
 
-   Converts an IMAP4 INTERNALDATE string to Coordinated Universal Time. Returns a
-   :mod:`time` module tuple.
-
+   Parse an IMAP4 ``INTERNALDATE`` string and return corresponding local
+   time.  The return value is a :class:`time.struct_time` tuple or
+   None if the string has wrong format.
 
 .. function:: Int2AP(num)
 
@@ -102,9 +102,13 @@
 
 .. function:: Time2Internaldate(date_time)
 
-   Converts a :mod:`time` module tuple to an IMAP4 ``INTERNALDATE`` representation.
-   Returns a string in the form: ``"DD-Mmm-YYYY HH:MM:SS +HHMM"`` (including
-   double-quotes).
+   Convert *date_time* to an IMAP4 ``INTERNALDATE`` representation.  The
+   return value is a string in the form: ``"DD-Mmm-YYYY HH:MM:SS
+   +HHMM"`` (including double-quotes).  The *date_time* argument can be a
+   number (int or float) represening seconds since epoch (as returned
+   by :func:`time.time`), a 9-tuple representing local time (as returned by
+   :func:`time.localtime`), or a double-quoted string.  In the last case, it
+   is assumed to already be in the correct format.
 
 Note that IMAP4 message numbers change as the mailbox changes; in particular,
 after an ``EXPUNGE`` command performs deletions the remaining messages are