diff --git a/core/src/main/scala/org/apache/spark/Aggregator.scala b/core/src/main/scala/org/apache/spark/Aggregator.scala
index 6e5ce9cf92513..848edcd922c30 100644
--- a/core/src/main/scala/org/apache/spark/Aggregator.scala
+++ b/core/src/main/scala/org/apache/spark/Aggregator.scala
@@ -30,9 +30,9 @@ import org.apache.spark.util.collection.{AppendOnlyMap, ExternalAppendOnlyMap}
  */
 @DeveloperApi
 case class Aggregator[K, V, C] (
-           createCombiner: V => C,
-           mergeValue: (C, V) => C,
-           mergeCombiners: (C, C) => C) {
+     createCombiner: V => C,
+     mergeValue: (C, V) => C,
+     mergeCombiners: (C, C) => C) {
 
   // When spilling is enabled sorting will happen externally, but not necessarily with an 
   // ExternalSorter.