diff --git a/train_model.py b/train_model.py
index fa57638..fb441dd 100644
--- a/train_model.py
+++ b/train_model.py
@@ -197,7 +197,7 @@ def signature(model, in_alphabet, max_len):
     mock_x = [('abc', 'xyz')]
     mock_text, _ = encode_str(mock_x, in_alphabet, max_len)
     mock_y = model(mock_text)
-    return mlflow.models.signature.infer_signature(mock_text, mock_y)
+    return mlflow.models.signature.infer_signature(mock_text.numpy(), mock_y.numpy())
 
 
 @ex.automain