def METHOD_NAME(fst: 'pynini.FstLike') -> 'pynini.FstLike':
    """
    Helper function for parsing number strings. Converts common cardinal strings (groups of three digits delineated by 'cardinal_separator' - see graph_utils)
    and converts to a string of digits:
        "1 000" -> "1000"
        "1.000.000" -> "1000000"
    Args:
        fst: Any pynini.FstLike object. Function composes fst onto string parser fst
    Returns:
        fst: A pynini.FstLike object
    """
    exactly_three_digits = DAMO_DIGIT ** 3  # for blocks of three
    up_to_three_digits = pynini.closure(DAMO_DIGIT, 1, 3)  # for start of string
    cardinal_string = pynini.closure(
        DAMO_DIGIT, 1
    )  # For string w/o punctuation (used for page numbers, thousand series)
    cardinal_string |= (
        up_to_three_digits
        + pynutil.delete(cardinal_separator)
        + pynini.closure(exactly_three_digits + pynutil.delete(cardinal_separator))
        + exactly_three_digits
    )
    return cardinal_string @ fst