--- a/Lib/decimal.py	Tue Feb 03 02:30:19 2009 +0000
+++ b/Lib/decimal.py	Tue Feb 03 03:54:28 2009 +0000
@@ -136,6 +136,7 @@
 
 import copy as _copy
 import math as _math
+import numbers as _numbers
 
 try:
     from collections import namedtuple as _namedtuple
@@ -3695,6 +3696,12 @@
 
     return self
 
+# Register Decimal as a kind of Number (an abstract base class).
+# However, do not register it as Real (because Decimals are not
+# interoperable with floats).
+_numbers.Number.register(Decimal)
+
+
 ##### Context class #######################################################