code: def _Open(self, path_spec, mode='rb'):
      
      if not path_spec.HasParent():
        raise errors.PathSpecError(
            'Unsupported path specification without parent.')
  
      file_object = resolver.Resolver.OpenFileObject(
          path_spec.parent, resolver_context=self._resolver_context)
  
      try:
        zip_file = zipfile.ZipFile(file_object, 'r')
      except:
        file_object.close()
        raise
  
      self._file_object = file_object
      self._zip_file = zip_file
docs: Opens the file system object defined by path specification.
  
      Args:
        path_spec (PathSpec): path specification of the file system.
        mode (Optional[str]): file access mode. The default is 'rb' which
            represents read-only binary.
  
      Raises:
        AccessError: if the access to open the file was denied.
        IOError: if the file system object could not be opened.
        PathSpecError: if the path specification is incorrect.
        ValueError: if the path specification is invalid.