diff --git a/lib/src/hive.dart b/lib/src/hive.dart
index 1361f4bd..865975f7 100644
--- a/lib/src/hive.dart
+++ b/lib/src/hive.dart
@@ -37,9 +37,9 @@ class Hive {
   /// ```
   static void registerAdapter<T>(
     String typeName,
-    T? Function(dynamic json) fromJson,
+    T? Function(dynamic json) fromJson, [
     Type? type,
-  ) {
+  ]) {
     _typeRegistry.register<T>(Isar.fastHash(typeName), fromJson, type);
   }