def get_splits_order_label(discourse_tree_splits):
    """
    This is used for training the parser. It is in the order of the splits in a pre-order traversal form,
    and represented using the index of the EDU immediately to the left of the split.
    This is called Parsing_Label in the original code.
    """
    return [split.left.span[1] for split in discourse_tree_splits]