Bug : Single Class label

[arita37]

bug with single class label.

bug in site-packages\pyod\models/base.py Line 347

bug code
                     self._classes =  len(np.unique(y)) 

 Correct code :

        if y is not None:
            check_classification_targets(y)
            self._classes = max(2, len(np.unique(y)) )
            warnings.warn(