docs: function Transfer(transfer, options) {
      this.main = transfer;
      this.$main = $(this.main);
  
      var defaultOption = {
          theme: window.bizui.theme,
          customClass: '',
          dataSource: [],
          keyMap: {
              id: 'id',
              title: 'title',
              chosen: 'chosen'
          },
          titles: ['请选择', '已选择'],
          noContent: '请新增选项'
      };
      this.options = $.extend(defaultOption, options || {});
      this.init(this.options);
  }