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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 _tdec(code: str, unit: str = 'C') -> str: """ Translates a 4-digit decimal temperature representation Ex: 1045 -> -4.5°C 0237 -> 23.7°C """

    ret = f"{'-' if code[0] == '1' else ''}{int(code[1:3])}.{code[3]}"
    if unit:
        ret += f'°{unit}'
    return ret