'Return the feature importances.
The importance of a feature is computed as the (normalized) total
reduction of the criterion brought by that feature.
It is also known as the Gini importance.
Returns
feature_importances_ : array, shape = [n_features]'

@property
def feature_importances_(self):

    check_is_fitted(self, 'tree_')
    return self.tree_.compute_feature_importances()
