code: def directed_bipartition_of_one(seq):
      
      bipartitions = list(bipartition_of_one(seq))
      return chain(bipartitions, reverse_elements(bipartitions))
docs: Generate directed bipartitions where one part is of length 1.
  
      Args:
          seq (Iterable): The sequence to partition.
  
      Returns:
          list[tuple[tuple]]: A list of tuples containing each of the two
          partitions.
  
      Example:
          >>> partitions = directed_bipartition_of_one((1, 2, 3))
          >>> list(partitions)  # doctest: +NORMALIZE_WHITESPACE
          [((1,), (2, 3)),
           ((2,), (1, 3)),
           ((3,), (1, 2)),
           ((2, 3), (1,)),
           ((1, 3), (2,)),
           ((1, 2), (3,))]