fix

Author: Me

tf2onnx/rewriter/bilstm_rewriter.py

@@ -55,7 +55,7 @@ def process_bilstm(g, bi_lstms):
             lstm_inputs.extend([lstm_fw.input[4], h_node.output[0], c_node.output[0]])
 
         direction = "bidirectional"
-        attr = {}
+        attr = {"direction": direction}
         for name in rnn_utils.onnx_rnn_attr_mapping[rnn_utils.ONNX_RNN_TYPE.LSTM]:
             attr_val = lstm_fw.get_attr_value(name)
             if attr_val:
@@ -65,7 +65,8 @@ def process_bilstm(g, bi_lstms):
                        for act in lstm_fw.get_attr_value("activations", [])]
         activations += [act.decode("utf-8")
                         for act in lstm_bw.get_attr_value("activations", [])]
-        attr.update({"direction": direction, "activations": activations})
+        if activations:
+            attr["activations"] = activations
 
         bi_lstm_node = g.make_node("LSTM", lstm_inputs, attr=attr, output_count=3)
         all_nodes.append(bi_lstm_node)