code: def get_ref_video(self, fname: str) -> str:
      ref_vid_name = f"test_{fname}.mp4"
      return pathmgr.get_local_path(
          os.path.join(self.ref_vid_dir, ref_vid_name)
      )
  
file_path: AugLy/augly/tests/video_tests/base_unit_test.py
imports: import filecmp
  import os
  import tempfile
  import unittest
  from typing import Any, Callable, Dict, List, Optional, Tuple
  from augly.tests import VideoAugConfig
  from augly.utils import pathmgr, TEST_URI
label_desc: Use image node_id 6 for calling the BaseVideoUnitTest obj's underlying member method code with example usage: obj.get_ref_video(fname) and returns: pathmgr