docs: function comparatorStr(comparator) {
      if (comparator === Workflo.Comparator.ne) {
          return ' other than';
      }
      else if (comparator === Workflo.Comparator.gt) {
          return ' greater than';
      }
      else if (comparator === Workflo.Comparator.lt) {
          return ' less than';
      }
      else {
          return '';
      }
  }