/**
 * Extension function. Here, String is known as receiver type. 
 * That means, we can call this function on any String. 
 * The extension function can be called only from the   
 * class where it is defined.
 */
fun String.extensionFun() {
     //We can access the receiver (Here, it is String) using "this" keyword inside the business logic
     println("from extension function: $this")
}