diff --git a/scripts/preprocess_spec.py b/scripts/preprocess_spec.py
index bc9c178f..ed591312 100644
--- a/scripts/preprocess_spec.py
+++ b/scripts/preprocess_spec.py
@@ -195,5 +195,5 @@ def main():
                       separators=(',', ': '), ensure_ascii=True)
     return 0
 
-
-sys.exit(main())
+if __name__ == '__main__':
+    sys.exit(main())