diff --git a/electrum/json_db.py b/electrum/json_db.py
index 850b46109..1d1a9ce9f 100644
--- a/electrum/json_db.py
+++ b/electrum/json_db.py
@@ -25,6 +25,7 @@
 import threading
 import copy
 import json
+from typing import TYPE_CHECKING
 
 from . import util
 from .util import WalletFileException