// immutable map and mutable map
val desserts = hashMapOf("whipped cream" to "cake", "chocolate" to "cookie")
println(desserts["chocolate"])
if( desserts.isNotEmpty()) {
    println("desserts size is  ${desserts.size}" )
}
// contains key
println(desserts.containsKey("chocolate")) //true

// contains value
println(desserts.containsValue("cake")) //true

// contains key
println(desserts.contains("chocolate")) //true
println("chocolate" in desserts) //true

val inventory = mutableMapOf("pancake" to 1)
inventory.put("cake", 3)
inventory.remove("pancake")
if( inventory.isNotEmpty()) {
    println("inventory size is  ${inventory.size}" )
}