diff --git a/lib/src/storage/tb_storage.dart b/lib/src/storage/tb_storage.dart
index 0ca8efa..a85bcc9 100644
--- a/lib/src/storage/tb_storage.dart
+++ b/lib/src/storage/tb_storage.dart
@@ -12,7 +12,7 @@ abstract class TbStorage<E> {
   ///
   /// If [defaultValue] is specified, it is returned in case the key does not
   /// exist.
-  Future<E>? getItem(String key, {E? defaultValue});
+  Future<E?> getItem(String key, {E? defaultValue});
 
   /// Checks whether the storage contains the [key].
   Future<bool> containsKey(String key);