Is "--add-protocol" for a zone not implemented?

[Markus-]

What would you like to be added: I want to manage des protocols of a zone by using this role.

#> firewall-cmd --zone=block --add-protocol=ipv6-icmp

Why is this needed: For Ipv6 I want to add ipv6-icmp in an easy way. https://firewalld.org/documentation/zone/options.html#protocol