code: function (key, value) {
          assertNotNull(key);
  
          var index = binarySearch(this.slot.keys, 0, this.slot.size, key, this.slot.comparer.compare);
  
          if (index >= 0) {
              error(ERROR_DUPLICATE_KEY);
          }
  
          this.insert(~index, key, value);
      }
docs: Adds an element with the specified key and value into the SortedList.
  @param {Object} key The key of the element to add.
  @param {Object} value The value of the element to add.