diff --git a/mitmproxy/script/concurrent.py b/mitmproxy/script/concurrent.py
index 87cdca968..7573f2a5c 100644
--- a/mitmproxy/script/concurrent.py
+++ b/mitmproxy/script/concurrent.py
@@ -29,6 +29,7 @@ def concurrent(fn):
             "script.concurrent (%s)" % fn.__name__,
             target=run
         ).start()
+    # Support @concurrent for class-based addons
     if "." in fn.__qualname__:
         return staticmethod(_concurrent)
     else: