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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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("Couldn't parse CSV column %r." % column)
    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')