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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 _dfromtimestamp(timestamp):
 """Custom date timestamp constructor. ditto """

    try:
        return datetime.date.fromtimestamp(timestamp)
    except OSError:
        timestamp -= time.timezone
        d = datetime.date(1970, 1, 1) + datetime.timedelta(seconds=timestamp)
        if _isdst(d):
            timestamp += 3600
            d = datetime.date(1970, 1, 1) + datetime.timedelta(seconds=timestamp)
        return d