code: def adaptive_universal_transformer_multilayer_tpu():
    
    hparams = adaptive_universal_transformer_base_tpu()
    hparams.num_inrecurrence_layers = 2
    hparams.mix_with_transformer = "before_ut,after_ut"
    hparams.num_mixedin_layers = 1
    hparams.transformer_ffn_type = "sepconv"
    # TODO(lukaszkaiser): the options below don't work on TPU yet, make them work.
    # hparams.add_step_timing_signal = True
    # hparams.add_sru = True
    # hparams.self_attention_type = "dot_product_relative_v2"
    # hparams.max_relative_position = 256
    return hparams
docs: Multi-layer config for adaptive Transformer on TPU.