1
import M5a._
2
3
assert(sread(Map(), 2) == 0)
4
assert(sread(Map(2 -> 1), 2) == 1)
5
assert(write(Map(), 1, 2) == Map(1 -> 2))
6
assert(write(Map(1 -> 0), 1, 2) == Map(1 -> 2))