code: function() {
      if (this.itemCount_ && this.getInput('EMPTY')) {
        this.removeInput('EMPTY');
      } else if (!this.itemCount_ && !this.getInput('EMPTY')) {
        this.appendDummyInput('EMPTY')
            .appendField(this.newQuote_(true))
            .appendField(this.newQuote_(false));
      }
      // Add new inputs.
      for (var i = 0; i < this.itemCount_; i++) {
        if (!this.getInput('ADD' + i)) {
          var input = this.appendValueInput('ADD' + i);
          if (i == 0) {
            input.appendField(Blockly.Msg.TEXT_JOIN_TITLE_CREATEWITH);
          }
        }
      }
      // Remove deleted inputs.
      while (this.getInput('ADD' + i)) {
        this.removeInput('ADD' + i);
        i++;
      }
    }
docs: Modify this block to have the correct number of inputs.
  @private
  @this Blockly.Block