diff --git a/src/dexorder/bin/mirror.py b/src/dexorder/bin/mirror.py
index 7186389..8999876 100644
--- a/src/dexorder/bin/mirror.py
+++ b/src/dexorder/bin/mirror.py
@@ -102,7 +102,7 @@ async def write_metadata( pools, mirror_pools ):
     for token in tokens:
         token['x'] = {'mock':True}
     with open(filename, 'w') as f:
-        generate_metadata(tokens, pool_dicts, f)
+        generate_metadata(tokens, pool_dicts, file=f)
     log.info(f'wrote {filename}')