diff --git a/generator/src/python.ml b/generator/src/python.ml
index 7b60b3e9..0e84dfc4 100644
--- a/generator/src/python.ml
+++ b/generator/src/python.ml
@@ -300,7 +300,9 @@ let commandline_parse env i m =
         Line "# in --json mode we don't have any other arguments";
         Line "if ('--json' in sys.argv or '-j' in sys.argv):";
         Block [
-            Line "return json.loads(sys.stdin.readline(),)";
+            Line "jsondict = json.loads(sys.stdin.readline(),)";
+            Line "jsondict['json'] = True";
+            Line "return jsondict";
         ];
         Line (sprintf "parser = argparse.ArgumentParser(description='%s')" m.Method.description);
         Line "parser.add_argument('-j', '--json', action='store_const', const=True, default=False, help='Read json from stdin, print json to stdout', required=False)";