val s = Series(Vec(1,2,3), Index(0,5,10))
s: org.saddle.Series[Int, Int] = [3 x 1] 0 -> 1 5 -> 2 10 -> 3
s(5,10) res0: org.saddle.Series[Int,Int] = [2 x 1] 5 -> 2 10 -> 3