Stop using string exceptions

Lib/bdb.py

@@ -6,7 +6,7 @@ import types
 
 __all__ = ["BdbQuit","Bdb","Breakpoint"]
 
-BdbQuit = 'bdb.BdbQuit' # Exception to give up completely
+class BdbQuit(Exception): pass
 
 
 class Bdb:

Lib/macpath.py

@@ -170,7 +170,7 @@ def expanduser(path):
     """Dummy to retain interface-compatibility with other operating systems."""
     return path
 
-norm_error = 'macpath.norm_error: path cannot be normalized'
+class norm_error(Exception): pass
 
 def normpath(s):
     """Normalize a pathname.  Will return the same result for