```data class Foo(val value: Boolean) var kodein ...

# kodein

[allanhasegawa]

data class Foo(val value: Boolean)

var kodein = Kodein {
    bind<Optional<Foo>> with singleton { Some(Foo(true)) }
    // others bindings
}

fun unbindFoo() {
    kodein = Kodein {
        extend(kodein)
        bind<Optional<Foo>>(override = true) with singleton { None }
    }
}