code: def xmoe_tr_2d():
    
    hparams = xmoe_tr_dense_2k()
    hparams.mesh_shape = "b0:2;b1:4"
    hparams.outer_batch_size = 4
    hparams.layout = "outer_batch:b0;inner_batch:b1,expert_x:b1,expert_y:b0"
    hparams.encoder_layers = ["self_att", "moe_2d"] * 4
    hparams.decoder_layers = ["self_att", "enc_att", "moe_2d"] * 4
    hparams.moe_hidden_size = 2048
    hparams.moe_experts_x = 4
    hparams.moe_experts_y = 4
    return hparams
docs: Mixture of experts (16 experts).
  
    623M Params, einsum=1.09e13
  
    Returns:
      a hparams