anchor.diff:  
       systemd.network.links = mkOption {
         default = {};
  -      type = with types; attrsOf (submodule [ linkOptions ]);
  +      type = with types; attrsOf (submodule [ { options = linkOptions; } ]);
         description = "Definition of systemd network links.";
       };
   
       systemd.network.netdevs = mkOption {
         default = {};
  -      type = with types; attrsOf (submodule [ netdevOptions ]);
  +      type = with types; attrsOf (submodule [ { options = netdevOptions; } ]);
         description = "Definition of systemd network devices.";
       };
   
       systemd.network.networks = mkOption {
         default = {};
  -      type = with types; attrsOf (submodule [ networkOptions networkConfig ]);
  +      type = with types; attrsOf (submodule [ { options = networkOptions; } networkConfig ]);
         description = "Definition of systemd networks.";
       };
   
  
positive.code:   };
  
    addressOptions = {
  
      addressConfig = mkOption {
        default = {};
        example = { Address = "192.168.0.100/24"; };
        type = types.addCheck (types.attrsOf unitOption) checkAddress;
        description = ''
          Each attribute in this set specifies an option in the
          <literal>[Address]</literal> section of the unit.  See
          <citerefentry><refentrytitle>systemd.network</refentrytitle>
          <manvolnum>5</manvolnum></citerefentry> for details.
        '';
      };
  
    };
  
    routeOptions = {
  
      routeConfig = mkOption {
        default = {};
        example = { Gateway = "192.168.0.1"; };
        type = types.addCheck (types.attrsOf unitOption) checkRoute;
        description = ''
          Each attribute in this set specifies an option in the
          <literal>[Route]</literal> section of the unit.  See
          <citerefentry><refentrytitle>systemd.network</refentrytitle>
          <manvolnum>5</manvolnum></citerefentry> for details.
        '';
      };
  
    };
  
    networkOptions = commonNetworkOptions // {
  
negative.code: 
      addresses = mkOption {
        default = [ ];
        type = with types; listOf (submodule addressOptions);
        description = ''
          A list of address sections to be added to the unit.  See
          <citerefentry><refentrytitle>systemd.network</refentrytitle>
  