code: def test_generate_exp_id():
      with tempfile.TemporaryDirectory() as tmp:
          with work_dir(tmp):
              subprocess.check_output(["git", "init"])
              subprocess.check_output(["touch", "a"])
              subprocess.check_output(["git", "add", "a"])
              subprocess.check_output(["git", "commit", "-m", "a"])
  
              id_a = pfrl.experiments.generate_exp_id()
              assert id_a == pfrl.experiments.generate_exp_id()
  
              assert id_a != pfrl.experiments.generate_exp_id("prefix")
  
      with tempfile.TemporaryDirectory() as tmp2:
          with work_dir(tmp2):
              subprocess.check_output(["git", "init"])
              subprocess.check_output(["touch", "b"])
              subprocess.check_output(["git", "add", "b"])
              subprocess.check_output(["git", "commit", "-m", "b"])
  
              id_b = pfrl.experiments.generate_exp_id()
              assert id_a != id_b
  
file_path: pfrl/tests/experiments_tests/test_prepare_output_dir.py
imports: import contextlib
  import itertools
  import json
  import os
  import subprocess
  import sys
  import tempfile
  import pytest
  import pfrl
label_desc: Use image node_id 3 for calling a global function with example usage: test_generate_exp_id() without return types