def append_targets(example):
    """Append targets to the example dictionary. Needed for Keras."""
    if len(target_names) == 1:
      return (example, example[target_names[0]])
    targets = {}
    for name in target_names:
      targets[name] = example[name]
    return (example, targets)
Append targets to the example dictionary. Needed for Keras.
trax/data/tf_inputs.py