Too Long; Didn't Read
In Kotlin, if you create a <em>List</em> or <em>Map</em>, it is Read-Only (<a href="https://stackoverflow.com/a/33738910/3286489">similar to Immutable, but slightly different</a>). What this means is, you have no <em>add</em> or <em>put</em> or <em>remove </em>function to add to or remove from the collection once it is constructed.