def convert_token_number(token_number: str) -> int:
    """Helper function to convert the token index from 1 and string based to 0 and int based index.

    Parameters
    ----------
    token_number : str
        The token number as it appears in the tsv.

    Returns
    -------
    int
        The word index as it's needed for the competency triple.
    """

    return int(token_number) - 1