Set Specific Operations

                  val numbers = setOf("one", "two", "three")
​
println(numbers union setOf("four", "five"))
println(setOf("four", "five") union numbers)
​
println(numbers intersect setOf("two", "one"))
println(numbers subtract setOf("three", "four"))
println(numbers subtract setOf("four", "three")) // same output
                

                    let numbers = setOf("one", "two", "three")
​
print(numbers union setOf("four", "five"))
print(setOf("four", "five") union numbers)
​
print(numbers intersect setOf("two", "one"))
print(numbers subtract setOf("three", "four"))
print(numbers subtract setOf("four", "three")) // same output