docs: def get_opener(filename):
    """
    Finds a matching opener that is registed with :func:`register_opener`
    and returns a tuple ``(suffix, opener)``. If there is no opener that
    can handle this filename, :class:`UnknownArchive` is raised.
    """
  
    for suffix, opener in openers.items():
      if filename.endswith(suffix):
        return suffix, opener
    raise UnknownArchive(filename)