import tensorflow as tf

            layers = [
                tf.concat([token_embeddings, token_embeddings], axis=2)
            ]

            n_lm_layers = len(lm_graph.lstm_outputs['forward'])
            for i in range(n_lm_layers):
                layers.append(
                    tf.concat(
                        [lm_graph.lstm_outputs['forward'][i],
                         lm_graph.lstm_outputs['backward'][i]],
                        axis=-1
                    )
                )

