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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 format_value(value, sf=3):
 """ convert a parameter value into a formatted string with certain significant figures :param value: the value to be formatted :param sf: number of significant figures :return: str """

    if isinstance(value, str):
        return value

    elif isinstance(value, list) or isinstance(value, np.ndarray):
        value = list(value)
        for i in range(len(value)):
            vv = format_value(value[i])
            value[i] = vv
        return "[" + ", ".join(value) + "]"

    elif value is None:
        return "N/A"

    else:
        fmt_str = "{0:.%ig}" % sf
        return fmt_str.format(value)