Hi everyone,
I am trying to use the CRFModelWrapper method following the tutorial as addons/layers_crf.ipynb at add_crf_tutorial · howl-anderson/addons · GitHub 2 to implement a Bi-LSTM -CRF neural-network for a multi-classes time-series NER problem, and it works in TF 2.7 in my PC. However, when I used the same code and same data runing in TF 2.6 environment, it pops out some errors(as shown below) regarding to the tfa-CRF layer.  So, could someone please let me know if the addons CRF layer is only compatible for the TF 2.7 version or this is because I made some mistakes? Thank you very much.
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "C:\Users\YenPangLai\anaconda3\envs\tf2p6\lib\site-packages\keras\engine\training.py", line 1134, in fit
    data_handler = data_adapter.get_data_handler(
  File "C:\Users\YenPangLai\anaconda3\envs\tf2p6\lib\site-packages\keras\engine\data_adapter.py", line 1383, in get_data_handler
    return DataHandler(*args, **kwargs)
  File "C:\Users\YenPangLai\anaconda3\envs\tf2p6\lib\site-packages\keras\engine\data_adapter.py", line 1138, in __init__
    self._adapter = adapter_cls(
  File "C:\Users\YenPangLai\anaconda3\envs\tf2p6\lib\site-packages\keras\engine\data_adapter.py", line 917, in __init__
    super(KerasSequenceAdapter, self).__init__(
  File "C:\Users\YenPangLai\anaconda3\envs\tf2p6\lib\site-packages\keras\engine\data_adapter.py", line 801, in __init__
    model.distribute_strategy.run(
  File "C:\Users\YenPangLai\anaconda3\envs\tf2p6\lib\site-packages\tensorflow\python\distribute\distribute_lib.py", line 1286, in run
    return self._extended.call_for_each_replica(fn, args=args, kwargs=kwargs)
  File "C:\Users\YenPangLai\anaconda3\envs\tf2p6\lib\site-packages\tensorflow\python\distribute\distribute_lib.py", line 2849, in call_for_each_replica
    return self._call_for_each_replica(fn, args, kwargs)
  File "C:\Users\YenPangLai\anaconda3\envs\tf2p6\lib\site-packages\tensorflow\python\distribute\distribute_lib.py", line 3632, in _call_for_each_replica
    return fn(*args, **kwargs)
  File "C:\Users\YenPangLai\anaconda3\envs\tf2p6\lib\site-packages\tensorflow\python\autograph\impl\api.py", line 597, in wrapper
    return func(*args, **kwargs)
  File "C:\Users\YenPangLai\anaconda3\envs\tf2p6\lib\site-packages\keras\engine\data_adapter.py", line 802, in <lambda>
    lambda x: model(x, training=False), args=(concrete_x,))
  File "C:\Users\YenPangLai\anaconda3\envs\tf2p6\lib\site-packages\keras\engine\base_layer.py", line 1037, in __call__
    outputs = call_fn(inputs, *args, **kwargs)
  File "<input>", line 47, in call
  File "C:\Users\YenPangLai\anaconda3\envs\tf2p6\lib\site-packages\keras\engine\base_layer.py", line 1037, in __call__
    outputs = call_fn(inputs, *args, **kwargs)
  File "C:\Users\YenPangLai\anaconda3\envs\tf2p6\lib\site-packages\tensorflow_addons\layers\crf.py", line 131, in call
    raise NotImplementedError(
NotImplementedError: Currently, CRF layer do not support left padding