diff --git a/geo_alarm.py b/geo_alarm.py
index 138248b..83b38da 100644
--- a/geo_alarm.py
+++ b/geo_alarm.py
@@ -120,9 +120,13 @@ def load_nowcast_geo_alarm_filter(path: Path) -> dict[str, Any]:
         if not isinstance(lightning, dict):
             raise ConfigurationError("filter.lightning JSON nesnesi olmalıdır.")
         event_type = lightning.get("type")
-        if event_type not in {"FLASH_CLOUD_TO_GROUND", "PULSE_IN_CLOUD"}:
+        if event_type is not None and event_type not in {
+            "FLASH_CLOUD_TO_GROUND",
+            "PULSE_IN_CLOUD",
+        }:
             raise ConfigurationError(
-                "filter.lightning.type FLASH_CLOUD_TO_GROUND veya PULSE_IN_CLOUD olmalıdır."
+                "filter.lightning.type belirtilirse FLASH_CLOUD_TO_GROUND veya "
+                "PULSE_IN_CLOUD olmalıdır."
             )
 
     thunderstorm = config.get("thunderstorm")