code: def test_mkdir_allow_fallback_success(tmp_path):
      dir_name = tmp_path / "valid" / "directory"
      assert mkdir_allow_fallback(dir_name) == dir_name
      assert dir_name.exists()
  
imports: import ctypes
  import errno
  import os
  import platform
  import re
  import shutil
  import sys
  import tempfile
  import time
  from concurrent.futures import ThreadPoolExecutor
  from pathlib import Path
  from unittest import mock
  from unittest.mock import Mock, patch
  import pytest
  from wandb.sdk.lib import filesystem
  from wandb.sdk.lib.filesystem import check_exists, copy_or_overwrite_changed, mkdir_allow_fallback, mkdir_exists_ok, reflink, safe_copy, safe_open, system_preferred_path
label_desc: Use image node_id 36 for calling a global function with example usage: test_mkdir_allow_fallback_success(tmp_path) without return types