code: def _version_from_git_tree(base_version: str) -> str | None:
      try:
          root_directory = os.path.dirname(os.path.realpath(__file__))
  
          # Get date string from date of most recent git commit.
          p = subprocess.Popen(
              ["git", "show", "-s", "--format=%at", "HEAD"],
              cwd=root_directory,
              stdout=subprocess.PIPE,
              stderr=subprocess.PIPE,
          )
          stdout, _ = p.communicate()
          timestamp = int(stdout.decode().strip())
          datestring = datetime.date.fromtimestamp(timestamp).strftime(
              "%Y%m%d"
          )
          assert datestring.isnumeric()
  
          # Get commit hash from most recent git commit.
          p = subprocess.Popen(
              ["git", "describe", "--long", "--always"],
              cwd=root_directory,
              stdout=subprocess.PIPE,
              stderr=subprocess.PIPE,
          )
          stdout, _ = p.communicate()
          commit_hash = stdout.decode().strip().rsplit("-g", 1)[-1]
          assert commit_hash.isalnum()
      except:
          return None
      else:
          return f"{base_version}.dev{datestring}+{commit_hash}"
  
file_path: jax/jax/version.py
imports: from __future__ import annotations
  import datetime
  import os
  import pathlib
  import subprocess
label_desc: Use image node_id 3 for calling a global function with example usage: _version_from_git_tree(base_version) and returns: base_version, str, datestring, str, commit_hash, None