docs: function(compute, newValue, oldValue, batchNum) {
              // Only trigger event when value has changed
              if (newValue !== oldValue) {
                  can.batch.trigger(compute, batchNum ? {
                          type: "change",
                          batchNum: batchNum
                      } : 'change', [
                          newValue,
                          oldValue
                      ]);
              }
          }