diff --git a/check_http_json.py b/check_http_json.py
index e242431..257256f 100755
--- a/check_http_json.py
+++ b/check_http_json.py
@@ -369,7 +369,7 @@ class JsonRuleProcessor:
 
         now = datetime.now(timezone.utc)
 
-        if timestamp.tzinfo == None:
+        if timestamp.tzinfo is None:
             timestamp = timestamp.replace(tzinfo=timezone.utc)
 
         age = now - timestamp