code: def __call__(self, data):
      data = copy.copy(data)
      data.y = data.y[:, target]  # Specify target.
      return data
  
file_path: pytorch_geometric/examples/qm9_nn_conv.py
imports: import copy
  import os.path
  import torch
  import torch.nn.functional
  from torch.nn import GRU, Linear, ReLU, Sequential
  import torch_geometric.transforms
  from torch_geometric.datasets import QM9
  from torch_geometric.loader import DataLoader
  from torch_geometric.nn import NNConv, Set2Set
  from torch_geometric.utils import remove_self_loops
label_desc: Use image node_id 1 for calling the MyTransform obj's underlying member method code with example usage: obj.__call__(data) and returns: data