code: def iterative_encoder_decoder(encoder_input,
                                encoder_self_attention_bias,
                                encoder_decoder_attention_bias,
                                query,
                                hparams):
    
    for _ in range(hparams.num_rec_steps):
      with tf.variable_scope("step", reuse=tf.AUTO_REUSE):
        encoder_output = image_question_encoder(
            encoder_input,
            encoder_self_attention_bias,
            hparams,
            query)
  
        decoder_output = decoder(
            query,
            encoder_output,
            None,
            encoder_decoder_attention_bias,
            hparams)
  
        encoder_input = encoder_output
        query = decoder_output
  
        return decoder_output
docs: Iterative encoder decoder.