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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 valid_station(station: str):
 """ Checks the validity of a station ident This function doesn't return anything. It merely raises a BadStation error if needed """

    station = station.strip()
    if len(station) != 4:
        raise BadStation('ICAO station idents must be four characters long')
    uses_na_format(station)