DatePicker not setting value

I am unable to get the DatePicker to return a value. I have tried setting this using the click, typed and arrow keys. Nothing helps.

I have put in the text example to show that this works. Here is my code.

import ipywidgets as w

text_box = w.Text(placeholder='Type Contract Name')
start_date_widget = w.DatePicker(description='Start Date')
display(text_box, start_date_widget)

start_date = start_date_widget.value
contract = text_box.value

print(contract, start_date)

'hello' None

Chrome browser, using jupyter notebook through jupyterhub, ipywidgets 7.0.

Any debugging for system info needed then please let me know. Thanks.

[jasongrout]

This is now fixed. Thanks again @JoshuaC3 and @pbugnion!

[jasongrout]

I think I would use object.keys