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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 decimal128_to_decimal(b):
    "decimal128 bytes to Decimal"
    v = decimal128_to_sign_digits_exponent(b)
    if isinstance(v, Decimal):
        return v
    sign, digits, exponent = v
    return Decimal((sign, Decimal(digits).as_tuple()[1], exponent))