Fix typo in documentation for collections.ChainMap, thanks to Olivier Bernard from docs@
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index dc76ea5..7979f07 100644
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -159,7 +159,7 @@
 
         d['x']                # Get first key in the chain of contexts
         d['x'] = 1            # Set value in current context
-        del['x']              # Delete from current context
+        del d['x']            # Delete from current context
         list(d)               # All nested values
         k in d                # Check all nested values
         len(d)                # Number of nested values
diff --git a/Misc/ACKS b/Misc/ACKS
index b137613..da7a434 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -101,6 +101,7 @@
 Michel Van den Bergh
 Julian Berman
 Brice Berna
+Olivier Bernard
 Eric Beser
 Steven Bethard
 Stephen Bevan