diff --git a/src/main/scala/com/github/pathikrit/dijon/package.scala b/src/main/scala/com/github/pathikrit/dijon/package.scala
index 27af80e..c554c20 100644
--- a/src/main/scala/com/github/pathikrit/dijon/package.scala
+++ b/src/main/scala/com/github/pathikrit/dijon/package.scala
@@ -61,8 +61,8 @@ package object dijon {
         a.foreach { case (k, v) =>
           res.put(k, if (b.contains(k)) v ++ b(k) else v.deepCopy)
         }
-        b.keys.foreach { k =>
-          if (!res.containsKey(k)) res.put(k, b(k).deepCopy)
+        b.foreach { case (k, v) =>
+          if (!res.containsKey(k)) res.put(k, v.deepCopy)
         }
         res.asScala
       case _ => that.deepCopy