anchor.diff:        type = with types; listOf (submodule ipv6PrefixOptions);
         description = ''
           A list of ipv6Prefix sections to be added to the unit.  See
  -        <citerefentry><refentrytitle>systemd.network</refentrytitle>
  -        <manvolnum>5</manvolnum></citerefentry> for details.
  -      '';
  -    };
  -
  -    dhcpServerConfig = mkOption {
  -      default = {};
  -      example = { PoolOffset = 50; EmitDNS = false; };
  -      type = types.addCheck (types.attrsOf unitOption) checkDhcpServer;
  -      description = ''
  -        Each attribute in this set specifies an option in the
  -        <literal>[DHCPServer]</literal> section of the unit.  See
  -        <citerefentry><refentrytitle>systemd.network</refentrytitle>
  -        <manvolnum>5</manvolnum></citerefentry> for details.
  -      '';
  -    };
  -
  -    linkConfig = mkOption {
  -      default = {};
  -      example = { Unmanaged = true; };
  -      type = types.addCheck (types.attrsOf unitOption) checkNetworkLink;
  -      description = ''
  -        Each attribute in this set specifies an option in the
  -        <literal>[Link]</literal> section of the unit.  See
           <citerefentry><refentrytitle>systemd.network</refentrytitle>
           <manvolnum>5</manvolnum></citerefentry> for details.
         '';
  
positive.code:             ${attrsToSection def.dhcpV6Config}
  
            ''}
            ${optionalString (def.ipv6PrefixDelegationConfig != {}) ''
              [IPv6PrefixDelegation]
              ${attrsToSection def.ipv6PrefixDelegationConfig}
  
negative.code:     xfrmConfig = mkOption {
        default = {};
        example = { InterfaceId = 1; };
        type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionXfrm;
        description = ''
          Each attribute in this set specifies an option in the
          <literal>[Xfrm]</literal> section of the unit.  See
          <citerefentry><refentrytitle>systemd.netdev</refentrytitle>
          <manvolnum>5</manvolnum></citerefentry> for details.
        '';
      };
  
      vrfConfig = mkOption {
        default = {};
        example = { Table = 2342; };
        type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionVRF;
        description = ''
          Each attribute in this set specifies an option in the
          <literal>[VRF]</literal> section of the unit. See
          <citerefentry><refentrytitle>systemd.netdev</refentrytitle>
          <manvolnum>5</manvolnum></citerefentry> for details.
          A detailed explanation about how VRFs work can be found in the
          <link xlink:href="https://www.kernel.org/doc/Documentation/networking/vrf.txt">kernel
          docs</link>.
        '';
      };
  
  