Add note about similarity between class methods and Delphi's virtual

class methods.

pep-0252.txt

@@ -381,10 +381,12 @@ Static methods and class methods
     receive an implicit first argument that is the *class* for which
     they are invoked.  This has no C++ or Java equivalent, and is not
     quite the same as what class methods are in Smalltalk, but may
-    serve a similar purpose.  (Python also has real metaclasses, and
-    perhaps methods defined in a metaclass have more right to the name
-    "class method"; but I expect that most programmers won't be using
-    metaclasses.)  Here's an example:
+    serve a similar purpose.  According to Armin Rigo, they are
+    similar to "virtual class methods" in Borland Pascal dialect
+    Delphi.  (Python also has real metaclasses, and perhaps methods
+    defined in a metaclass have more right to the name "class method";
+    but I expect that most programmers won't be using metaclasses.)
+    Here's an example:
 
       class C: