High in the Pyrenees, on the border between Spain and France, lies the tiny principality of Caesia. Ancient Caesian statues depict the Horae as blindfolded and its people say that "Lady time is blind." The prime meridian happens to pass right through Caesia, which made Universal Time its official time. Caesia has never observed the barbaric practice of meddling with the clock known as Daylight Savings. When Leap Seconds were introduced, the people of Caesia devised an ingenious plan to thwart this new abomination: they have announced that their time zone UTC offset shall be adjusted by one second for every leap second added to UTC. By using the same mechanism that makes it possible for other countries to declare an entire hour as non-existent in local time at the beginning of Daylight Savings the people of Caesia have abolished the 61st second that is occasionally added to the last minute of the last day of June or December. This ensures that civilian time is still officially based on UTC, is well-defined as a proper time zone and can even be described in the tzfile(5) format - and yet never has a day that is not exactly 86400 SI seconds. Caesia had an atomic clock installed in its national labs in 1958. Their far-sighted metrologists had already suggested then to switch its time definition to this standard. Had they done so back in 1958, their clock would have been numerically equivalent to TAI, before the divorce of the second from the rotation of the Earth. However, the final ratification and implementation of this change took a while and only came into effect in 1980. By sheer coincidence, this makes Caesia Standard Time numerically equivalent to GPS time. The "gaps" in conversion from Caesia Standard Time to UTC all correspond to UTC Leap Seconds. It is well-known that gaps at one end of a timezone conversion correspond to "folds" at the other end - a period that occurs twice. Until recently, there was no support for folds in the datetime library of the Python language (Caesians are avid Pythonistas). Now that PEP495 has been implemented they are keen to check how well the datetime library interoperates with their unusual (yet completely well-formed and valid) time zone definition. Can you help them? Oren