fn join_three(a string, b string, c string) string {
	return a + b + c
}

fn join_four(a string, b string, c string, d string) string {
	return a + b + c + d
}

fn main() {
	assert join_three('a', 'b', 'c') == 'abc'
	assert join_four('a', 'b', 'c', 'd') == 'abcd'
}