anchor.diff:            [DHCPv6]
             ${attrsToSection def.dhcpV6Config}
           ''
  +        + optionalString (def.dhcpV6PrefixDelegationConfig != { }) ''
  +          [DHCPv6PrefixDelegation]
  +          ${attrsToSection def.dhcpV6PrefixDelegationConfig}
  +        ''
           + optionalString (def.dhcpServerConfig != { }) ''
             [DHCPServer]
             ${attrsToSection def.dhcpServerConfig}
  
positive.code:           "IPv6ProxyNDP"
            "IPv6ProxyNDPAddress"
            "IPv6PrefixDelegation"
            "IPv6MTUBytes"
            "Bridge"
            "Bond"
  
negative.code:       description = ''
          Each attribute in this set specifies an option in the
          <literal>[DHCPv6]</literal> section of the unit.  See
          <citerefentry><refentrytitle>systemd.network</refentrytitle>
          <manvolnum>5</manvolnum></citerefentry> for details.
        '';
      };
  
      dhcpV6PrefixDelegationConfig = mkOption {
        default = {};
        example = { SubnetId = "auto"; Announce = true; };
        type = types.addCheck (types.attrsOf unitOption) check.network.sectionDHCPv6PrefixDelegation;
        description = ''
          Each attribute in this set specifies an option in the
          <literal>[DHCPv6PrefixDelegation]</literal> section of the unit. See
          <citerefentry><refentrytitle>systemd.network</refentrytitle>
          <manvolnum>5</manvolnum></citerefentry> for details.
        '';
  