code: def load_dataset():
      r"""
  
      Load dataset objects.
  
      Returns: PyG dataset object
  
      """
      format = cfg.dataset.format
      name = cfg.dataset.name
      dataset_dir = cfg.dataset.dir
      # Try to load customized data format
      for func in register.loader_dict.values():
          dataset = func(format, name, dataset_dir)
          if dataset is not None:
              return dataset
      # Load from Pytorch Geometric dataset
      if format == "PyG":
          dataset = load_pyg(name, dataset_dir)
      # Load from OGB formatted data
      elif format == "OGB":
          dataset = load_ogb(name.replace("_", "-"), dataset_dir)
      else:
          raise ValueError("Unknown data format: {}".format(format))
      return dataset
  
file_path: GraphGym/graphgym/loader_pyg.py
imports: from typing import Callable
  import torch
  import torch_geometric.transforms
  from torch_geometric.datasets import PPI, Amazon, Coauthor, KarateClub, MNISTSuperpixels, Planetoid, QM7b, TUDataset
  from torch_geometric.loader import ClusterLoader, DataLoader, GraphSAINTEdgeSampler, GraphSAINTNodeSampler, GraphSAINTRandomWalkSampler, NeighborSampler, RandomNodeSampler
  from torch_geometric.utils import index_to_mask, negative_sampling, to_undirected
  import graphgym.register
  from graphgym.config import cfg
  from graphgym.models.transform import create_link_label, neg_sampling_transform
label_desc: Use image node_id 5 for calling a global function with example usage: load_dataset() and returns: dataset, dataset