import tensorflow as tf

                'softmax_w', [hidden_size, vocab_size], dtype=tf.float32)
            softmax_b = tf.get_variable('softmax_b', [vocab_size], dtype=tf.float32)
            logits = tf.nn.xw_plus_b(output, softmax_w, softmax_b)
            logits = tf.reshape(logits, [self.batch_size, self.num_steps, vocab_size])

            loss = tf.contrib.seq2seq.sequence_loss(
