SF patch #1227568, Expression AST node not documented.
diff --git a/Misc/ACKS b/Misc/ACKS
index 34ebc5d..58a2c86 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -316,6 +316,7 @@
 Bob Kahn
 Kurt B. Kaiser
 Tamito Kajiyama
+Peter van Kampen
 Jacob Kaplan-Moss
 Lou Kates
 Sebastien Keim