<!--
  Note: if the issue is about documentation or the website, please file it at:
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**Do you want to request a *feature* or report a *bug*?**

bug.

**What is the current behavior?**

```js
  renderer.create(
    <Fragment>
      <Fragment>foo</Fragment>
    </Fragment>
  )
  .toTree()
```

> Invariant Violation: toTree() does not yet know how to handle nodes with tag=10

https://codesandbox.io/s/olky92m01y

**What is the expected behavior?**

returns a tree.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**

16.2.0

return emptyObject;
  },
  prepareForCommit(): void {
    
  },
  resetAfterCommit(): void {
    
  },
  createInstance(
    type: string,
    props: Props,
    rootContainerInstance: Container,
    hostContext: Object,
    internalInstanceHandle: Object,
  ): Instance {
    return {
      type,
      props,
      children: [],
      rootContainerInstance,
      tag: 'INSTANCE',
    };
  },
  appendInitialChild(
    parentInstance: Instance,
    child: Instance | TextInstance,
  ): void {
    const index = parentInstance.children.indexOf(child);
    if (index !== -1) {
      parentInstance.children.splice(index, 1);