bug in passing complexe type - 2

In Example: [Advanced attributes](https://codepen.io/codemeasandwich/pen/rgdvPX)

This done NOT works !!
```
Html`<a-b></a-b><a-person  hi=${this.onHi} x=${{a:2}} name="Beckett"/>`
```
DOM out put -> `<a-b></a-b><a-person  hi="function () { [native code] }" name="Beckett" x="[object Object]">`