def utcfromtimestamp(cls, t):
        "Construct a UTC datetime from a POSIX timestamp (like time.time())."
        t, frac = divmod(t, 1.0)
        us = int(frac * 1e6)

        # If timestamp is less than one microsecond smaller than a
        # full second, us can be rounded up to 1000000.  In this case,
        # roll over to seconds, otherwise, ValueError is raised
        # by the constructor.
        if us == 1000000:
            t += 1
            us = 0
        y, m, d, hh, mm, ss, weekday, jday, dst = _time.gmtime(t)
        ss = min(ss, 59)    # clamp out leap seconds if the platform has them
        return cls(y, m, d, hh, mm, ss, us)
Construct a UTC datetime from a POSIX timestamp (like time.time()).