Use docstrings for exception classes
diff --git a/Lib/bdb.py b/Lib/bdb.py
index b05ed22..d5b051b 100644
--- a/Lib/bdb.py
+++ b/Lib/bdb.py
@@ -6,7 +6,8 @@
 
 __all__ = ["BdbQuit","Bdb","Breakpoint"]
 
-class BdbQuit(Exception): pass
+class BdbQuit(Exception):
+    """Exception to give up completely"""
 
 
 class Bdb:
diff --git a/Lib/macpath.py b/Lib/macpath.py
index 2881c32..6501fcd 100644
--- a/Lib/macpath.py
+++ b/Lib/macpath.py
@@ -170,7 +170,8 @@
     """Dummy to retain interface-compatibility with other operating systems."""
     return path
 
-class norm_error(Exception): pass
+class norm_error(Exception):
+    """Path cannot be normalized"""
 
 def normpath(s):
     """Normalize a pathname.  Will return the same result for