SF patch #820195 by Wojtek Walczak (gminick at users.sourceforge.net):
make obj.__contains__() returns True/False instead of 1/0.
diff --git a/Misc/ACKS b/Misc/ACKS
index 74bfbfa..67c1cec 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -572,6 +572,7 @@
 Charles Waldman
 Richard Walker
 Larry Wall
+Wojtek Walczak
 Greg Ward
 Barry Warsaw
 Steve Waterbury