Exception during training: 'MultiOutputClassifier' object has no attribute 'best_score_'
joblib.externals.loky.process_executor._RemoteTraceback: 
"""
Traceback (most recent call last):
  File "/home/prudencio/anaconda3/envs/py37/lib/python3.7/site-packages/joblib/externals/loky/process_executor.py", line 431, in _process_worker
    r = call_item()
  File "/home/prudencio/anaconda3/envs/py37/lib/python3.7/site-packages/joblib/externals/loky/process_executor.py", line 285, in __call__
    return self.fn(*self.args, **self.kwargs)
  File "/home/prudencio/anaconda3/envs/py37/lib/python3.7/site-packages/joblib/_parallel_backends.py", line 595, in __call__
    return self.func(*args, **kwargs)
  File "/home/prudencio/anaconda3/envs/py37/lib/python3.7/site-packages/joblib/parallel.py", line 253, in __call__
    for func, args, kwargs in self.items]
  File "/home/prudencio/anaconda3/envs/py37/lib/python3.7/site-packages/joblib/parallel.py", line 253, in <listcomp>
    for func, args, kwargs in self.items]
  File "/home/prudencio/src/padmet/padmet/models/supervised/helpers.py", line 370, in sk_forward_helper
    refit=True, n_jobs=-1, scoring=scoring)
  File "/home/prudencio/src/padmet/padmet/models/supervised/helpers.py", line 173, in fit
    valid_score = validation._validate_best_score_(model)
  File "/home/prudencio/src/padmet/padmet/utils/validation.py", line 146, in _validate_best_score_
    res = model.best_score_
AttributeError: 'MultiOutputClassifier' object has no attribute 'best_score_'
"""

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/prudencio/src/padmet/bin/train.py", line 45, in main
    train(**training_params, output_path=output_path)
  File "/home/prudencio/src/padmet/padmet/train.py", line 83, in train
    model.fit_score(train_dataset=train, valid_dataset=valid, test_dataset=test, **fit_params)
  File "/home/prudencio/src/padmet/padmet/models/base.py", line 574, in fit_score
    ckp_path=ckp_path, **kwargs)
  File "/home/prudencio/src/padmet/padmet/models/base.py", line 543, in score
    ys_preds = self.forward(episodes, task_ckpt_path=None)
  File "/home/prudencio/src/padmet/padmet/models/base.py", line 260, in forward
    return self.network(xs, *args, **kwargs)
  File "/home/prudencio/anaconda3/envs/py37/lib/python3.7/site-packages/torch/nn/modules/module.py", line 727, in _call_impl
    result = self.forward(*input, **kwargs)
  File "/home/prudencio/src/padmet/padmet/models/supervised/sklearners.py", line 68, in forward
    for ep in episodes)
  File "/home/prudencio/anaconda3/envs/py37/lib/python3.7/site-packages/joblib/parallel.py", line 1042, in __call__
    self.retrieve()
  File "/home/prudencio/anaconda3/envs/py37/lib/python3.7/site-packages/joblib/parallel.py", line 921, in retrieve
    self._output.extend(job.get(timeout=self.timeout))
  File "/home/prudencio/anaconda3/envs/py37/lib/python3.7/site-packages/joblib/_parallel_backends.py", line 542, in wrap_future_result
    return future.result(timeout=timeout)
  File "/home/prudencio/anaconda3/envs/py37/lib/python3.7/concurrent/futures/_base.py", line 435, in result
    return self.__get_result()
  File "/home/prudencio/anaconda3/envs/py37/lib/python3.7/concurrent/futures/_base.py", line 384, in __get_result
    raise self._exception
AttributeError: 'MultiOutputClassifier' object has no attribute 'best_score_'