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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 _digi_nan(fmt):
 """ Return the wfdb digital value used to store nan for the format type. Parmeters --------- fmt : str, or list The wfdb dat format, or a list of them. """

    if isinstance(fmt, list):
        return [_digi_nan(f) for f in fmt]

    if fmt == '80':
        return -128
    if fmt == '310':
        return -512
    if fmt == '311':
        return -512
    elif fmt == '212':
        return -2048
    elif fmt == '16':
        return -32768
    elif fmt == '61':
        return -32768
    elif fmt == '160':
        return -32768
    elif fmt == '24':
        return -8388608
    elif fmt == '32':
        return -2147483648