code: def _GetCachedFileByPath(self, key_path_upper):
      
      longest_key_path_prefix_upper = ''
      longest_key_path_prefix_length = len(longest_key_path_prefix_upper)
      for key_path_prefix_upper in self._registry_files:
        if key_path_upper.startswith(key_path_prefix_upper):
          key_path_prefix_length = len(key_path_prefix_upper)
          if key_path_prefix_length > longest_key_path_prefix_length:
            longest_key_path_prefix_upper = key_path_prefix_upper
            longest_key_path_prefix_length = key_path_prefix_length
  
      if not longest_key_path_prefix_upper:
        return None, None
  
      registry_file = self._registry_files.get(
          longest_key_path_prefix_upper, None)
      return longest_key_path_prefix_upper, registry_file
docs: Retrieves a cached Windows Registry file for a key path.
  
      Args:
        key_path_upper (str): Windows Registry key path, in upper case with
            a resolved root key alias.
  
      Returns:
        tuple: consist:
  
          str: key path prefix
          WinRegistryFile: corresponding Windows Registry file or None if not
              available.