1 

     2 import Resit._

     3 

     4 

     5 assert(removeOne(List(1,2,3,2,1), 3) == List(1, 2, 2, 1))

     6 assert(removeOne(List(1,2,3,2,1), 2) == List(1, 3, 2, 1))

     7 assert(removeOne(List(1,2,3,2,1), 1) == List(2, 3, 2, 1))

     8 assert(removeOne(List(1,2,3,2,1), 0) == List(1, 2, 3, 2, 1))

     9 assert(removeOne(List("a", "b", "b"), "b") == List("a", "b"))