Getting `TraitError: The 'children' trait of a VBox instance contains an Instance of a TypedTuple which expected a Widget, not the Viewer at '0x2aaab5d0ad00'.`

when running the code below in Jupyter Lab

```python
import itkwidgets
import ipywidgets

view = itkwidgets.view(geometries=None, background=[0.0, 0.0, 0.0])

# Headings
heading = ipywidgets.HTML(value="

Heading

# Output Widget
widget = ipywidgets.VBox(children = [heading, view])
```

Below are my versions of packages.

> itkwidgets 1.0a16 pypi_0 pypi
> ipywidgets 7.6.5 pyhd3eb1b0_1 defaults

When running with version 0.X of `itkwidgets` this error does not occur

> itkwidgets 0.32.0 py38h32f6830_0 conda-forge