diff --git a/core/storage/license_plate.py b/core/storage/license_plate.py
index b0c7194..4c5b703 100644
--- a/core/storage/license_plate.py
+++ b/core/storage/license_plate.py
@@ -99,11 +99,13 @@ class LicensePlateManager:
 
     async def _listen_for_messages(self):
         """Listen for messages on the license_results channel."""
+        listen_generator = None
         try:
             if not self.pubsub:
                 return
 
-            async for message in self.pubsub.listen():
+            listen_generator = self.pubsub.listen()
+            async for message in listen_generator:
                 if message['type'] == 'message':
                     try:
                         # Log the raw message from Redis channel
@@ -121,8 +123,20 @@ class LicensePlateManager:
 
         except asyncio.CancelledError:
             logger.info("License plate subscription task cancelled")
+            # Properly close the async generator
+            if listen_generator is not None:
+                try:
+                    await listen_generator.aclose()
+                except Exception as e:
+                    logger.debug(f"Error closing listen generator: {e}")
         except Exception as e:
             logger.error(f"Error in license plate message listener: {e}", exc_info=True)
+            # Properly close the async generator on error
+            if listen_generator is not None:
+                try:
+                    await listen_generator.aclose()
+                except Exception as e:
+                    logger.debug(f"Error closing listen generator: {e}")
 
     async def _process_license_plate_result(self, data: Dict[str, Any]):
         """
diff --git a/requirements.base.txt b/requirements.base.txt
index af22160..094f332 100644
--- a/requirements.base.txt
+++ b/requirements.base.txt
@@ -4,4 +4,5 @@ ultralytics
 opencv-python
 scipy
 filterpy
-psycopg2-binary
\ No newline at end of file
+psycopg2-binary
+lap>=0.5.12
\ No newline at end of file