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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 fromtimestamp(timestamp):
 """Because python doesn't support negative timestamp to datetime so we have to implement my own method """

    if timestamp >= 0:
        return datetime.fromtimestamp(timestamp)
    else:
        return datetime(1969, 12, 31, 20, 0) + timedelta(seconds=timestamp)