code: def _unpack_field(examples, field):
      return [e[field] for e in examples]
  
file_path: dgl/examples/pytorch/jtnn/jtnn/datautils.py
imports: import dgl
  import torch
  from dgl.data.utils import _get_dgl_url, download, extract_archive, get_download_dir
  from torch.utils.data import Dataset
  from .jtmpn import ATOM_FDIM, BOND_FDIM, mol2dgl_single
  from .mol_tree import Vocab
  from .mol_tree_nx import DGLMolTree
  from .mpn import mol2dgl_single
label_desc: Use image node_id 1 for calling a global function with example usage: _unpack_field(examples, field) and returns: unknown