code: def custom_decoder(self, ae_config):
      return Decoder_MLP_Custom(ae_config)
  
imports: import os
  from copy import deepcopy
  import pytest
  import torch
  from pythae.models import RAE_L2, RAE_L2_Config
  from pythae.trainers import CoupledOptimizerTrainer, CoupledOptimizerTrainerConfig
  from tests.data.custom_architectures import *
label_desc: Use image node_id 4 for calling the Test_Main_Training obj's underlying member method code with example usage: obj.custom_decoder(ae_config) and returns: Decoder_MLP_Custom