Added the constants ascii_letters, ascii_lowercase, and ascii_uppercase
to the string module.  This was determined to be the right approach in
SF bug #226706.
diff --git a/Lib/string.py b/Lib/string.py
index 913d980..d682fc7 100644
--- a/Lib/string.py
+++ b/Lib/string.py
@@ -24,6 +24,9 @@
 lowercase = 'abcdefghijklmnopqrstuvwxyz'
 uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
 letters = lowercase + uppercase
+ascii_lowercase = lowercase
+ascii_uppercase = uppercase
+ascii_letters = ascii_lowercase + ascii_uppercase
 digits = '0123456789'
 hexdigits = digits + 'abcdef' + 'ABCDEF'
 octdigits = '01234567'