struct ReceiverPatternExpect[T] {
	value T
}

fn (e ReceiverPatternExpect[[]T]) array_item(value T) T {
	if e.value.len == 0 {
		return value
	}
	return e.value[0]
}

fn (e ReceiverPatternExpect[map[K]V]) map_value(key K, value V) V {
	if key in e.value {
		return e.value[key]
	}
	return value
}

fn main() {
	ReceiverPatternExpect[map[string]int]{
		value: {
			'one': 1
		}
	}.array_item(0)
	ReceiverPatternExpect[[]int]{
		value: [1, 2, 3]
	}.map_value(0, 0)
}