diff --git a/apns.py b/apns.py
index a1a8b68..ac1a9b2 100644
--- a/apns.py
+++ b/apns.py
@@ -84,6 +84,7 @@ class Payload:
         return f"{COMMANDS[self.command]}: {self.fields}"
     
 import courier
+from hashlib import sha1
 
 class APNSConnection(): 
     def __init__(self, token: bytes=None, private_key=None, cert=None):
@@ -108,6 +109,13 @@ class APNSConnection():
         if 3 in resp.fields.fields:
             self.token = resp.fields.fields[3]
 
+    def filter(self, topics: list[str]):
+        payload = Payload(9, Fields({1: self.token, 2: b"".join([sha1(topic.encode()).digest() for topic in topics])}))
+
+        self.sock.write(payload.to_bytes())
+
+    
+
 if __name__ == "__main__":
     import courier
     import base64
diff --git a/demo.py b/demo.py
index a6b90e3..4b82754 100644
--- a/demo.py
+++ b/demo.py
@@ -8,11 +8,8 @@ print(f"Push Token 1: {b64encode(conn1.token).decode()}")
 conn2 = apns.APNSConnection()
 print(f"Push Token 2: {b64encode(conn2.token).decode()}")
 
-# Create a topic filter payload with SHA1 hash of the topic
-payload = apns.Payload(9, apns.Fields({1: conn2.token, 2: sha1(b"com.apple.madrid").digest()}))
-# Send the payload
-#conn1.sock.write(payload.to_bytes())
-conn2.sock.write(payload.to_bytes())
+conn1.filter(["com.apple.madrid"])
+conn2.filter(["com.apple.madrid"])
 
 #print(sha1(b"com.apple.madrid").digest())
 # Send a notification