Fixed subscribe topic bug (#417)

Fixed subscribe topic bug

CHANGELOG.rst

@@ -1,6 +1,12 @@
 Brewtils Changelog
 ==================
 
+3.20.1
+------
+TBD
+
+- Fixed an issue where topics could repeat when using topic in @subscribe
+
 3.20.0
 ------
 11/1/2023

brewtils/decorators.py

@@ -399,17 +399,23 @@ def returnTrue(self):
         topics: A list of topics to subscribe to
     """
 
-    if topic:
-        topics.append(topic)
+    subscribe_topics = []
+    if topic and topic not in subscribe_topics:
+        subscribe_topics.append(topic)
+
+    if topics:
+        for list_topic in topics:
+            if list_topic not in subscribe_topics:
+                subscribe_topics.append(list_topic)
 
     if _wrapped is None:
-        return functools.partial(subscribe, topics=topics)
+        return functools.partial(subscribe, topics=subscribe_topics)
 
     # Python 2 compatibility
     if hasattr(_wrapped, "__func__"):
-        _wrapped.__func__.subscribe_topics = topics
+        _wrapped.__func__.subscribe_topics = subscribe_topics
     else:
-        _wrapped.subscribe_topics = topics
+        _wrapped.subscribe_topics = subscribe_topics
 
     return _wrapped