The purpose of this program is to practice the mental arithmetic of the Doomsday rule/algorithm.
The Doomsday rule was devised by John Conway in 1973. It works due to the Gregorian calendar moving in cycles of 400 years. Conway is also famous for his "Conway's Game of Life."
Verify you have all the packages installed, then run Python3 with
python main.py. This will return a random date between 1980-01-01 and
2030-12-31. If you wish to know the day of the week of a given date, run
python main.py --reveal=YYYY-MM-DD which will return a day of the week.