code: function(_set1, _set2) {
          var hash = {}, uniq = [],
              fullSet = _set1.concat(_set2);
  
          for (var i = 0; i < fullSet.length; i++) {
              if (fullSet[i] !== undefined) hash[fullSet[i].toString()] = fullSet[i];
          }
  
          for (var key in hash) {
              uniq.push(hash[key]);
          }
          return uniq;
      }
docs: Returns a set of elements
  with distinct string representation.
  @param _set1
  @param _set2
  @returns {Array}