code: def get_commit_hash():
      """If Ludwig is run from a git repository, get the commit hash of the current HEAD.
  
      Returns None if git is not executable in the current environment or Ludwig is not run in a git repo.
      """
      try:
          with open(os.devnull, "w") as devnull:
              is_a_git_repo = (
                  subprocess.call(
                      ["git", "branch"],
                      stderr=subprocess.STDOUT,
                      stdout=devnull,
                  )
                  == 0
              )
          if is_a_git_repo:
              commit_hash = subprocess.check_output(
                  ["git", "rev-parse", "HEAD"]
              ).decode("utf-8")
              return commit_hash
      except:  # noqa: E722
          pass
      return None
  
imports: import copy
  import functools
  import os
  import random
  import subprocess
  import weakref
  from collections import OrderedDict
  from collections.abc import Mapping
  from typing import Any, Dict, TYPE_CHECKING
  import numpy
  import torch
  from ludwig.api_annotations import DeveloperAPI
  from ludwig.constants import PROC_COLUMN
  from ludwig.globals import DESCRIPTION_FILE_NAME
  from ludwig.utils import fs_utils
  from ludwig.utils.fs_utils import find_non_existing_dir_by_adding_suffix
label_desc: Use image node_id 16 for calling a global function with example usage: get_commit_hash() and returns: None, commit_hash