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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 _mktime(time_struct):
 """Custom mktime because Windows can't be arsed to properly do pre-Epoch dates, probably because it's busy counting all its chromosomes. """

    try:
        return time.mktime(time_struct)
    except OverflowError:
        dt = datetime.datetime(*time_struct[:6])
        ep = datetime.datetime(1970, 1, 1)
        diff = dt - ep
        ts = diff.days * 24 * 3600 + diff.seconds + time.timezone
        if time_struct.tm_isdst == 1:
            ts -= 3600
        # Guess if DST is in effect for -1
        if time_struct.tm_isdst == -1 and _isdst(dt):
            ts -= 3600
        return ts