diff --git a/adafruit_minimqtt/adafruit_minimqtt.py b/adafruit_minimqtt/adafruit_minimqtt.py
index 0b5e51fd..6ca9b05e 100755
--- a/adafruit_minimqtt/adafruit_minimqtt.py
+++ b/adafruit_minimqtt/adafruit_minimqtt.py
@@ -364,7 +364,7 @@ def add_topic_callback(self, mqtt_topic, callback_method):
         """Registers a callback_method for a specific MQTT topic.
 
         :param str mqtt_topic: MQTT topic identifier.
-        :param str callback_method: Name of callback method.
+        :param function callback_method: Name of callback method.
         """
         if mqtt_topic is None or callback_method is None:
             raise ValueError("MQTT topic and callback method must both be defined.")