Widgets shouldn't fail when values are set to None

[CoreyBurger]

trafficstars

Description

If you are trying to set the value of some widgets, you cannot set them to None - such as Label, Text or selection

Reproduce

Create widget Get data from source Try and set value of widget to data, if None or NULL, get error

Expected behavior

The widget should be set to a value of Null

Why? Because a Null value maybe be the expected or needed value. And there are plenty of times when blanking data is the right thing to do.

Context

ipywidgets==7.6.3