diff --git a/qt/aqt/addons.py b/qt/aqt/addons.py
index 23a42a00d..29093ff90 100644
--- a/qt/aqt/addons.py
+++ b/qt/aqt/addons.py
@@ -47,8 +47,8 @@ class AddonInstallationResult(NamedTuple):
 
 class AddonManager:
 
-    ext = ".ankiaddon"
-    _manifest_schema = {
+    ext: str = ".ankiaddon"
+    _manifest_schema: dict = {
         "type": "object",
         "properties": {
             "package": {"type": "string", "meta": False},
diff --git a/qt/aqt/main.py b/qt/aqt/main.py
index d759cf34a..2cc6cf7ad 100644
--- a/qt/aqt/main.py
+++ b/qt/aqt/main.py
@@ -1027,6 +1027,7 @@ QTreeWidget {
 
     def installAddon(self, path):
         from aqt.addons import installAddonPackages
+
         installAddonPackages(self.addonManager, [path], external=True, parent=self)
 
     # Cramming
@@ -1482,7 +1483,7 @@ will be lost. Continue?"""
 
     def onAppMsg(self, buf: str) -> Optional[QTimer]:
         is_addon = buf.endswith(".ankiaddon")
-        
+
         if self.state == "startup":
             # try again in a second
             return self.progress.timer(
@@ -1521,13 +1522,13 @@ Please ensure a profile is open and Anki is not busy, then try again."""
             self.raise_()
         if buf == "raise":
             return None
-        
+
         # import / add-on installation
         if is_addon:
             self.installAddon(buf)
         else:
             self.handleImport(buf)
-        
+
         return None
 
     # GC
diff --git a/qt/aqt/utils.py b/qt/aqt/utils.py
index c32c409dc..6b22c8f27 100644
--- a/qt/aqt/utils.py
+++ b/qt/aqt/utils.py
@@ -57,7 +57,7 @@ def showInfo(
     type="info",
     title="Anki",
     textFormat=None,
-    customBtns=None
+    customBtns=None,
 ):
     "Show a small info window with an OK button."
     if parent is False: