'Construct a UTC datetime from a POSIX timestamp (like time.time()).'

@classmethod
def utcfromtimestamp(cls, t):

    (t, frac) = divmod(t, 1.0)
    us = int((frac * 1000000.0))
    if (us == 1000000):
        t += 1
        us = 0
    (y, m, d, hh, mm, ss, weekday, jday, dst) = _time.gmtime(t)
    ss = min(ss, 59)
    return cls(y, m, d, hh, mm, ss, us)
