diff --git a/axes/handlers/cache.py b/axes/handlers/cache.py
index 423c592..b85f3f6 100644
--- a/axes/handlers/cache.py
+++ b/axes/handlers/cache.py
@@ -29,8 +29,8 @@ class AxesCacheHandler(AbstractAxesHandler, AxesBaseHandler):
     def reset_attempts(
         self,
         *,
-        ip_address: str = None,
-        username: str = None,
+        ip_address: Optional[str] = None,
+        username: Optional[str] = None,
         ip_or_username: bool = False,
     ) -> int:
         cache_keys: list = []
diff --git a/requirements-qa.txt b/requirements-qa.txt
index 7489a2f..34e30d6 100644
--- a/requirements-qa.txt
+++ b/requirements-qa.txt
@@ -1,4 +1,4 @@
 black==22.10.0
-mypy==0.982
+mypy==0.990
 prospector==1.7.7
 types-pkg_resources  # Type stub