code: def _get_file_type(input_file: str) -> str:
      """Get type of input file. Must be csv/pkl/sdf/joblib file."""
      filename, file_extension = os.path.splitext(input_file)
      # If gzipped, need to compute extension again
      if file_extension == ".gz":
          filename, file_extension = os.path.splitext(filename)
      if file_extension == ".csv":
          return "csv"
      elif file_extension == ".pkl":
          return "pickle"
      elif file_extension == ".joblib":
          return "joblib"
      elif file_extension == ".sdf":
          return "sdf"
      else:
          raise ValueError("Unrecognized extension %s" % file_extension)
  
imports: import joblib
  import gzip
  import pickle
  import os
  import tempfile
  import tarfile
  import zipfile
  import logging
  from urllib.request import urlretrieve
  from typing import Any, Iterator, List, Optional, Tuple, Union, cast, IO
  import pandas
  import numpy
  import deepchem
label_desc: Use image node_id 13 for calling a global function with example usage: _get_file_type(input_file) and returns: str, str, str, str