go =>
foreach(Y in [1600,1700,1899,1900,2000,2006,2012])
println(Y=cond(leap_year(Y),leap_year,not_leap_year))
end,
nl.
leap_year(Year) =>
(Year mod 4 == 0, Year mod 100 != 0)
;
Year mod 400 == 0.