ipywidgets unobserve functools partial code example

Example: ipywidgets unobserve functools partial

import ipywidgets as widgets
w = widgets.Text()
w.unobserve(None,...)
            
# still need to pass `names` whenever needed. 
# But at least you don't need to know the exact name of the handler. 
# Specially if you have used a `partial` when setting the observer.