docs: def _locate_file(self, pattern, root=os.path.dirname('revokests_key.py')):
          """Locate all files matching supplied filename pattern in and below
  
          supplied root directory.
          """
  
          for path, dirs, files in os.walk(os.path.abspath(root)):
              for filename in fnmatch.filter(files, pattern):
                  return os.path.join(path, filename)