code: def _check_installed(self, prefix, cuda, lib, version, filenames):
      install_root = os.path.join(prefix, cuda, lib, version)
      assert os.path.isdir(install_root)
      for _x, _y, files in os.walk(install_root):
          for filename in filenames:
              if filename in files:
                  return
      pytest.fail("expected file cound not be found")
  
file_path: cupy/tests/cupyx_tests/tools_tests/test_install_library.py
imports: import os
  import platform
  import tempfile
  import urllib
  from cupy import testing
  from cupyx.tools import install_library
  import pytest
label_desc: Use image node_id 5 for calling the TestInstallLibrary obj's underlying member method code with example usage: obj._check_installed(prefix, cuda, lib, version, filenames) without return types