code: function(datePicker) {
          var self = this;
  
          datePicker.on('open', function() {
              self.textPainter.blockFocusingOut();
          });
  
          datePicker.on('close', function() {
              var focusModel = self.focusModel;
              var address = focusModel.which();
              var rowKey = address.rowKey;
              var columnName = address.columnName;
              var changedValue = self.$focusedInput.val();
  
              self.textPainter.unblockFocusingOut();
  
              // when the datePicker layer is closed, selected date must set on input element.
              if (focusModel.isEditingCell(rowKey, columnName)) {
                  focusModel.dataModel.setValue(rowKey, columnName, changedValue);
              }
              focusModel.finishEditing();
          });
      }
docs: Bind custom event on the DatePicker instance
  @param {DatePicker} datePicker - instance of DatePicker
  @private