'Signed distance to the separating hyperplane.
Signed distance is positive for an inlier and negative for an outlier.
Parameters
X : array-like, shape (n_samples, n_features)
Returns
X : array-like, shape (n_samples,)
Returns the decision function of the samples.'

def decision_function(self, X):

    dec = self._decision_function(X)
    return dec
