anchor.diff:  
       bindsTo = mkOption {
         default = [];
  -      type = types.listOf types.string;
  +      type = types.listOf types.str;
         description = ''
           Like ‘requires’, but in addition, if the specified units
           unexpectedly disappear, this unit will be stopped as well.
  
positive.code:     };
  
      script = mkOption {
        type = types.str;
        default = "";
        description = "Shell commands executed as the service's main process.";
      };
  
negative.code: 
      requires = mkOption {
        default = [];
        type = types.listOf types.str;
        description = ''
          Start the specified units when this unit is started, and stop
          this unit when the specified units are stopped or fail.
  