docs: update form api example link

components/form/index.en-US.md

@@ -117,7 +117,7 @@ After wrapped by `getFieldDecorator`, `value`(or other property defined by `valu
 | id | The unique identifier is required. support [nested fields format](https://github.com/react-component/form/pull/48). | string |  |
 | options.getValueFromEvent | Specify how to get value from event or other onChange arguments | function(..args) | [reference](https://github.com/react-component/form#option-object) |
 | options.initialValue | You can specify initial value, type, optional value of children node. (Note: Because `Form` will test equality with `===` internaly, we recommend to use vairable as `initialValue`, instead of literal) |  | n/a |
-| options.normalize | Normalize value to form component, [a select-all example](https://codepen.io/afc163/pen/JJVXzG?editors=001) | function(value, prevValue, allValues): any | - |
+| options.normalize | Normalize value to form component, [a select-all example](https://codesandbox.io/s/kw4l2vqqmv) | function(value, prevValue, allValues): any | - |
 | options.rules | Includes validation rules. Please refer to "Validation Rules" part for details. | object\[] | n/a |
 | options.trigger | When to collect the value of children node | string | 'onChange' |
 | options.validateFirst | Whether stop validate on first rule of error for this field. | boolean | false |

components/form/index.zh-CN.md

@@ -116,7 +116,7 @@ CustomizedForm = Form.create({})(CustomizedForm);
 | id | 必填输入控件唯一标志。支持嵌套式的写法。 | string |  |
 | options.getValueFromEvent | 可以把 onChange 的参数（如 event）转化为控件的值 | function(..args) | [reference](https://github.com/react-component/form#option-object) |
 | options.initialValue | 子节点的初始值，类型、可选值均由子节点决定(注意：由于内部校验时使用 `===` 判断是否变化，建议使用变量缓存所需设置的值而非直接使用字面量)) |  |  |
-| options.normalize | 转换默认的 value 给控件，[一个选择全部的例子](https://codepen.io/afc163/pen/JJVXzG?editors=001) | function(value, prevValue, allValues): any | - |
+| options.normalize | 转换默认的 value 给控件，[一个选择全部的例子](https://codesandbox.io/s/kw4l2vqqmv) | function(value, prevValue, allValues): any | - |
 | options.rules | 校验规则，参考下方文档 | object\[] |  |
 | options.trigger | 收集子节点的值的时机 | string | 'onChange' |
 | options.validateFirst | 当某一规则校验不通过时，是否停止剩下的规则的校验 | boolean | false |