text: Title: Problem about param ml_task="regression",
  Body: If I use this param, it will raise an issue below for all of the model, if it is deleted, the model works fine.
  
  '<' not supported between instances of 'numpy.ndarray' and 'str'
  Traceback (most recent call last):
    File "C:\Users\ZHENGJ\AppData\Local\Programs\Python\Python39\lib\site-packages\supervised\base_automl.py", line 1195, in _fit
      trained = self.train_model(params)
    File "C:\Users\ZHENGJ\AppData\Local\Programs\Python\Python39\lib\site-packages\supervised\base_automl.py", line 404, in train_model
      self.keep_model(mf, model_subpath)
    File "C:\Users\ZHENGJ\AppData\Local\Programs\Python\Python39\lib\site-packages\supervised\base_automl.py", line 317, in keep_model
      self.select_and_save_best()
    File "C:\Users\ZHENGJ\AppData\Local\Programs\Python\Python39\lib\site-packages\supervised\base_automl.py", line 1315, in select_and_save_best
      self._best_model = min(
  TypeError: '<' not supported between instances of 'numpy.ndarray' and 'str'