def __get_noise_range(db: float) -> int:
    """Returns the lower limit of one of the six pre-defined dB ranges based on dB.
    """
    if db >= 70.0:
        return 70
    elif db >= 65.0:
        return 65
    elif db >= 60.0:
        return 60
    elif db >= 55.0:
        return 55
    elif db >= 50.0:
        return 50
    else:
        return 40