def parse_treasury_csv_column(column):
    """
    Parse a treasury CSV column into a more human-readable format.

    Columns start with 'RIFLGFC', followed by Y or M (year or month), followed
    by a two-digit number signifying number of years/months, followed by _N.B.
    We only care about the middle two entries, which we turn into a string like
    3month or 30year.
    """
    column_re = re.compile(
        r"^(?P<prefix>RIFLGFC)"
        "(?P<unit>[YM])"
        "(?P<periods>[0-9]{2})"
        "(?P<suffix>_N.B)$"
    )

    match = column_re.match(column)
    if match is None:
        raise ValueError(column % "Couldn't parse CSV column %r.")
    unit, periods = get_unit_and_periods(match.groupdict())

    # Roundtrip through int to coerce '06' into '6'.
    return str(int(periods)) + ('year' if unit == 'Y' else 'month')
dataset/ETHPy150Open quantopian/zipline/zipline/data/treasuries.py/parse_treasury_csv_column/swapped operands of `%`