diff --git a/custom_components/sigmesh_gateway/config_flow.py b/custom_components/sigmesh_gateway/config_flow.py
index 1b4e78b..f1d5262 100644
--- a/custom_components/sigmesh_gateway/config_flow.py
+++ b/custom_components/sigmesh_gateway/config_flow.py
@@ -6,6 +6,7 @@ from typing import Any
 
 import voluptuous as vol
 from homeassistant import config_entries
+from homeassistant.core import callback
 from homeassistant.data_entry_flow import FlowResult
 from homeassistant.helpers import selector