Index: Lib/imaplib.py
===================================================================
--- Lib/imaplib.py	(revision 88101)
+++ Lib/imaplib.py	(working copy)
@@ -1308,8 +1308,8 @@
 
 
 
-Mon2num = {'Jan': 1, 'Feb': 2, 'Mar': 3, 'Apr': 4, 'May': 5, 'Jun': 6,
-        'Jul': 7, 'Aug': 8, 'Sep': 9, 'Oct': 10, 'Nov': 11, 'Dec': 12}
+Mon2num = {b'Jan': 1, b'Feb': 2, b'Mar': 3, b'Apr': 4, b'May': 5, b'Jun': 6,
+        b'Jul': 7, b'Aug': 8, b'Sep': 9, b'Oct': 10, b'Nov': 11, b'Dec': 12}
 
 def Internaldate2tuple(resp):
     """Convert IMAP4 INTERNALDATE to UT.
@@ -1335,7 +1335,7 @@
     # INTERNALDATE timezone must be subtracted to get UT
 
     zone = (zoneh*60 + zonem)*60
-    if zonen == '-':
+    if zonen == b'-':
         zone = -zone
 
     tt = (year, mon, day, hour, min, sec, -1, -1, -1)
Index: Lib/test/test_imaplib.py
===================================================================
--- Lib/test/test_imaplib.py	(revision 88101)
+++ Lib/test/test_imaplib.py	(working copy)
@@ -23,6 +23,9 @@
 
 class TestImaplib(unittest.TestCase):
 
+    def test_Internaldate2tuple(self):
+        self.assertEqual(imaplib.Internaldate2tuple(b'25 (INTERNALDATE "01-Apr-2000 19:02:23 -0700")')[0:6], (2000, 4, 1, 19, 2, 23))
+
     def test_that_Time2Internaldate_returns_a_result(self):
         # We can check only that it successfully produces a result,
         # not the correctness of the result itself, since the result