diff --git a/src/app/app.py b/src/app/app.py
index 07a31a1..d0ddf75 100644
--- a/src/app/app.py
+++ b/src/app/app.py
@@ -248,7 +248,7 @@ argument_parser = argparse.ArgumentParser("Web service")
 argument_parser.add_argument(
     "--host",
     default="0.0.0.0",
-    required=False
+    required=False,
     type=str,
     help="Host to serve on."
 )