code: def symbol_targets_bottom(x, model_hparams, vocab_size):
    
    if (model_hparams.shared_embedding_and_softmax_weights or
        model_hparams.get("shared_embedding")):
      try:
        return _symbol_bottom_simple(
            x, model_hparams, vocab_size, "shared", reuse=True)
      except ValueError:
        # perhaps there were no inputs, and this is a new variable.
        return _symbol_bottom_simple(
            x, model_hparams, vocab_size, "shared", reuse=None)
    else:
      return _symbol_bottom_simple(
          x, model_hparams, vocab_size, "target_emb", reuse=None)
docs: Bottom transformation for target symbols.