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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 _dtfromtimestamp(timestamp):
 """Custom datetime timestamp constructor. because Windows. again. """

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