def nn_y(self, y, k=1, radius=np.inf, eps=0.0, p=2):
        """Find the k nearest neighbors of y in the observed output data
        @see Databag.nn() for argument description
        @return  distance and indexes of found nearest neighbors.
        """
        assert len(y) == self.dim_y
        k_y = min(k, self.size)
        return self._nn(DATA_Y, y, k=k_y, radius=radius, eps=eps, p=p)
Find the k nearest neighbors of y in the observed output data
        @see Databag.nn() for argument description
        @return  distance and indexes of found nearest neighbors.