def __call__(self, step_input, states):  
return super(Seq2SeqDecoder, self).__call__(step_input, states)<EOL>
r"""One-step decoding of the input

        Parameters
        ----------
        step_input : NDArray
            Shape (batch_size, C_in)
        states : list
            The previous states of the decoder
        Returns
        -------
        step_output : NDArray
            Shape (batch_size, C_out)
        states : list
        step_additional_outputs : list
            Additional outputs of the step, e.g, the attention weights