val immutableSet = Set(1, 2, 3, 4)
val newSet = immutableSet + 5 // Adds a single element
val anotherSet = immutableSet ++ Set(6, 7) // Adds multiple elements
println(newSet)
println(anotherSet)
/*
run:
HashSet(5, 1, 2, 3, 4)
HashSet(1, 6, 2, 7, 3, 4)
*/