diff --git a/examples/addons/options-simple.py b/examples/addons/options-simple.py
index 6014bc8f9..6895a23be 100644
--- a/examples/addons/options-simple.py
+++ b/examples/addons/options-simple.py
@@ -3,7 +3,7 @@ Add a new mitmproxy option.
 
 Usage:
 
-    mitmproxy -s options-simple.py --set addheader true
+    mitmproxy -s options-simple.py --set addheader=true
 """
 from mitmproxy import ctx