@Bean
fun imageProcess(repo: MongoRepository) = CommandLineRunner {...}

// 1 + 2 + 3 is an expression that resolves to an Integer value.
// Therefore, the return type is Int
fun intExpression() = 1 + 2 + 3

// false && true is an expression that resolves to a Boolean value.
// Therefore, the return type is Boolean
fun boolExpression() = false && true

// The when here is a fully exhaustive when expression
// It can resolve to an Integer or a String.
// Therefore the return type is the common subtype of both
// Integer and String which happens to be Any (the root of the Kotlin type heirarchy.
fun anyExpression(foo: Boolean) = when(foo) {
    true -> 1
    else -> "Hello"
}