Unsupported format string passed to NoneType.__format__

[tdpauw]

$ ./bin/togglu timesheet --workspace-id 509982 --since 2022-04-01
...
04/12/22   | A Company                    |       1.09
04/11/22   | Another Company          |       3.59
04/11/22   | Yet Another Company   |       5.58
04/11/22   | XYZ Conference            |       1.26
Traceback (most recent call last):
  File "/Users/thipau/projects/thinkinglabs/togglu/./bin/togglu", line 12, in <module>
    cli.execute()
  File "/Users/thipau/projects/thinkinglabs/togglu/togglu/togglu.py", line 39, in execute
    args.func(args)
  File "/Users/thipau/projects/thinkinglabs/togglu/togglu/togglu.py", line 55, in timesheet
    renderer.render(
  File "/Users/thipau/projects/thinkinglabs/togglu/togglu/timesheet_console_renderer.py", line 17, in render
    f'{date_entry.date.strftime("%x"):<10} | '
TypeError: unsupported format string passed to NoneType.__format__