# pick-first-value data expression

# empty configs are not accepted by Kea
default-lease-time 1800;

# reduce literals
class "literal" {
    match if option dhcp6.client-data =
        pick-first-value(substring("abcd",0,0),null,"foobar");
}

# null
class "null" {
    match if option dhcp6.client-data = pick(null);
}