diff --git a/hci.py b/hci.py
index 7aaffed..30ade9b 100644
--- a/hci.py
+++ b/hci.py
@@ -8,7 +8,7 @@ class HCIBroadcaster:
     def __init__(self, b64key):
         self.key = base64.b64decode(b64key)
 
-    def _advertisement_template():
+    def _advertisement_template(self):
         adv = ""
         adv += "1e"  # length (30)
         adv += "ff"  # manufacturer specific data