Fix line-in selection

Fixes #141 (closed)

src/aura_engine/resources.py

@@ -67,7 +67,7 @@ class ResourceMapping:
         """
         return self.resource_mapping.get(resource_type)
 
-    def live_channel_for_resource(channel: str):
+    def live_channel_for_resource(self, channel: str):
         """
         Return the channel enum for a given live channel string from Tank.
         """