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.targetHost = mkOption {
        default = config.networking.hostName;
        description = ''
          This option specifies a hostname or IP address which can be
          used by <command>nixos-deploy-network</command> to execute
  
negative.code:     deployment.ec2.type = mkOption {
        default = "ec2";
        example = "nova";
        type = types.uniq types.string;
        description = ''
          Specifies the type of cloud.  This affects the machine
          configuration.  Current values are <literal>"ec2"</literal>
  