anchor.diff:  
         description = "Defnixos services to run on the machine.";
       };
  +
  +    defnixos.defnix = mkOption {
  +      default = defnix;
  +
  +      type = types.uniq types.attrs;
  +
  +      description = "The composed defnix set to use.";
  +    };
     };
   
     config = {
  
positive.code: 
      users.extraUsers = builtins.listToAttrs (map (name: {
        inherit name;
        value.uid = defnix.eval-support.calculate-id name;
      }) cfg.users);
    };
  }
  
negative.code:     defnixos.strongswan-service = mkOption {
        description = "An already-composed strongswan defnixos service function";
  
        default = cfg.defnix.defnixos.services.strongswan;
  
        type = types.uniq types.unspecified;
      };
  