Add a version tag to the decimal module.
diff --git a/Lib/decimal.py b/Lib/decimal.py
index dfc7043..1d12e87 100644
--- a/Lib/decimal.py
+++ b/Lib/decimal.py
@@ -134,6 +134,8 @@
     'setcontext', 'getcontext', 'localcontext'
 ]
 
+__version__ = '1.68'    # Highest version of the spec this complies with
+
 import copy as _copy
 import math as _math
 import numbers as _numbers