code: def _copy_problem_hparams(p_hparams):
    
    p = p_hparams
    # Duplicate input modality.
    p.modality["targets"] = p.modality["inputs"]
    # Duplicate input vocab size.
    p.vocab_size["targets"] = p.vocab_size["inputs"]
    # Duplicate input vocabulary.
    p.vocabulary["targets"] = p.vocabulary["inputs"]
    # Duplicate input space ids.
    p.target_space_id = p.input_space_id
    # Mark that p was reversed.
    p.was_copy = True
docs: Use input modality, vocab, and space id for target.