added n_classes_ attribute definition
@@ -470,6 +470,9 @@ class OneVsOneClassifier(BaseEstimator, ClassifierMixin, MetaEstimatorMixin):
classes_ : numpy array of shape [n_classes]
Array containing labels.
+ n_classes_ : int
+ Number of classes
+
pairwise_indices_ : list, length = ``len(estimators_)``, or ``None``
Indices of samples used when training the estimators.
``None`` when ``estimator`` does not have ``_pairwise`` attribute.
