Improve keras output order detection (#1489)

Signed-off-by: Tom Wildenhain <[email protected]>

Author: TomWildenhain-Microsoft

tf2onnx/convert.py

@@ -334,11 +334,14 @@ def wrap_call(*args, training=False, **kwargs):
 
     initialized_tables = None
     tensors_to_rename = tensor_names_from_structed(concrete_func, input_names, output_names)
+    reverse_lookup = {v: k for k, v in tensors_to_rename.items()}
 
     if model.output_names:
         # model.output_names is an optional field of Keras models indicating output order. It is None if unused.
-        reverse_lookup = {v: k for k, v in tensors_to_rename.items()}
         output_names = [reverse_lookup[out] for out in model.output_names]
+    elif isinstance(concrete_func.structured_outputs, dict):
+        # Other models specify output order using the key order of structured_outputs
+        output_names = [reverse_lookup[out] for out in concrete_func.structured_outputs.keys()]
 
     with tf.device("/cpu:0"):
         frozen_graph = tf_loader.from_function(concrete_func, input_names, output_names, large_model=large_model)