Minor codestyle update
diff --git a/README.md b/README.md
index cdade24..766cae6 100644
--- a/README.md
+++ b/README.md
@@ -6,11 +6,16 @@
 
 ## Versions
 
+### v0.3.2
+
+- Fix CooccurrenceAlgorithm with unknown item ids
+
 ### v0.3.1
 
 - Add CooccurrenceAlgorithm.
-  To use this algorithm, override engine.json by engine-cooccurrence.json,
-  or specify `--variant engine-cooccurrence.json` parameter for both pio train **and** deploy
+  To use this algorithm, override `engine.json` by `engine-cooccurrence.json`,
+  or specify `--variant engine-cooccurrence.json` parameter for both `$pio train` **and**
+  `$pio deploy`
 
 ### v0.3.0
 
diff --git a/src/main/scala/CooccurrenceAlgorithm.scala b/src/main/scala/CooccurrenceAlgorithm.scala
index 54ff741..3834ead 100644
--- a/src/main/scala/CooccurrenceAlgorithm.scala
+++ b/src/main/scala/CooccurrenceAlgorithm.scala
@@ -59,7 +59,8 @@
     val userItem = events
       // map item from string to integer index
       .flatMap {
-        case ViewEvent(user, item, _) if itemStringIntMap.contains(item) => Some(user, itemStringIntMap(item))
+        case ViewEvent(user, item, _) if itemStringIntMap.contains(item) =>
+          Some(user, itemStringIntMap(item))
         case _ => None
       }
       // if user view same item multiple times, only count as once