code: def __init__(self, model_config: ModelConfig):
      super().__init__()
      self.model_config = model_config
  
      if model_config.mode.value == "multiclass_classification":
          out_channels = 7
      else:
          out_channels = 1
  
      self.conv1 = GCNConv(3, 16)
      self.conv2 = GCNConv(16, out_channels)
  
file_path: pytorch_geometric/test/contrib/explain/test_pgm_explainer.py
imports: import pytest
  import torch
  from torch_geometric.contrib.explain import PGMExplainer
  from torch_geometric.explain import Explainer
  from torch_geometric.explain.config import ModelConfig
  from torch_geometric.nn import GCNConv, global_add_pool
  from torch_geometric.testing import withPackage
label_desc: Use image node_id 1 to create a new GCN object from inherited base classes: torch.nn with example: obj = GCN(model_config)