code: def parse_treasury_csv_column(column):
      
      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')
docs: 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.