code: def planar_flow(self, model_configs):
      model = PlanarFlow(model_configs)
      return model
  
imports: import os
  from copy import deepcopy
  import numpy
  import pytest
  import torch
  from pydantic import ValidationError
  from pythae.data.datasets import BaseDataset
  from pythae.models import AutoModel
  from pythae.models.base.base_utils import ModelOutput
  from pythae.models.normalizing_flows import NFModel, PlanarFlow, PlanarFlowConfig
  from pythae.pipelines import TrainingPipeline
  from pythae.trainers import BaseTrainer, BaseTrainerConfig
label_desc: Use image node_id 4 for calling the Test_PlanarFlow_Training obj's underlying member method code with example usage: obj.planar_flow(model_configs) and returns: model