anchor.diff:  
       deployment.adhoc.destroyVMCommand = mkOption {
         default = "destroy-vm";
  +      type = types.uniq types.string;
         description = ''
           Remote command to destroy a previously created NixOS virtual
           machine.
  
positive.code: 
      deployment.adhoc.controller = mkOption {
        example = "cloud.example.org";
        description = ''
          Hostname or IP addres of the machine to which
          <command>nixos-deploy-network</command> should connect (via
  
negative.code:     deployment.targetEnv = mkOption {
        default = "none";
        example = "ec2";
        type = types.uniq types.string;
        description = ''
          This option specifies the type of the environment in which the
          machine is to be deployed by
  