code: def fake_metric(y_hat, y):
      return (y_hat - y).mean()
  
imports: import copy
  import os
  import numpy
  import pytest
  import torch
  from pytorch_tabular import TabularModel, TabularModelTuner, model_sweep
  from pytorch_tabular.config import DataConfig, OptimizerConfig, TrainerConfig
  from pytorch_tabular.config.config import SSLModelConfig
  from pytorch_tabular.feature_extractor import DeepFeatureExtractor
  from pytorch_tabular.models import AutoIntConfig, CategoryEmbeddingModelConfig, FTTransformerConfig, GANDALFConfig, GatedAdditiveTreeEnsembleConfig, NodeConfig, TabNetModelConfig
  from pytorch_tabular.ssl_models import DenoisingAutoEncoderConfig
  from scipy.stats import randint, uniform
  from sklearn.metrics import accuracy_score, r2_score
  from sklearn.model_selection import KFold
label_desc: Use image node_id 1 for calling a global function with example usage: fake_metric(y_hat, y) and returns: unknown