a few more modules get __all__
diff --git a/Lib/mhlib.py b/Lib/mhlib.py
index f5ece05..dbfa9e1 100644
--- a/Lib/mhlib.py
+++ b/Lib/mhlib.py
@@ -82,6 +82,7 @@
 import shutil
 from bisect import bisect
 
+__all__ = ["MH","Error","Folder","Message"]
 
 # Exported constants