code: def create_dataset(self) -> Dataset:
      if self.subset not in ["MIT", "STEREO", "50K", "FULL"]:
          raise ValueError(
              "Valid Subset names are MIT, STEREO and 50K."
          )
  
      if self.subset == "MIT":
          dataset_url = USPTO_MIT_URL
  
      if self.subset == "STEREO":
          dataset_url = USPTO_STEREO_URL
  
      if self.subset == "50K":
          dataset_url = USPTO_50K_URL
  
      if self.subset == "FULL":
          dataset_url = USPTO_FULL_URL
          if self.splitter == "SpecifiedSplitter":
              raise ValueError(
                  "There is no pre computed split for the full dataset, use a custom split instead!"
              )
  
      dataset_file = os.path.join(self.data_dir, self.name + ".csv")
  
      if not os.path.exists(dataset_file):
          logger.info("Downloading dataset...")
          dc.utils.data_utils.download_url(
              url=dataset_url, dest_dir=self.data_dir
          )
          logger.info("Dataset download complete.")
  
      loader = dc.data.CSVLoader(
          tasks=self.tasks,
          feature_field="reactions",
          featurizer=self.featurizer,
      )
  
      return loader.create_dataset(dataset_file, shard_size=8192)
  
file_path: deepchem/deepchem/molnet/load_function/uspto_datasets.py
imports: import os
  import logging
  from typing import List, Optional, Tuple, Union
  import deepchem
  from deepchem.data import Dataset
  from deepchem.molnet.load_function.molnet_loader import TransformerGenerator, _MolnetLoader
label_desc: Use image node_id 2 for calling the _USPTOLoader obj's underlying member method code with example usage: obj.create_dataset() and returns: loader