Filtering by end fails on version 18.1.1

[RoyLarson]

I get an error when I write the below query

λ eliot-tree logs\2020-06-01_0006.log --select "log_level=='DEBUG'" --end "2020-06-01T14:40:48"
Traceback (most recent call last):
  File "%userprofile%\.venv\Scripts\eliot-tree-script.py", line 9, in <module>
    sys.exit(main())
  File "%userprofile%\.venv\lib\site-packages\eliottree\_cli.py", line 178, in main
    human_readable=args.human_readable)
  File "%userprofile%\.venv\lib\site-packages\eliottree\_cli.py", line 92, in display_tasks
    colorize=colorize)
  File "%userprofile%\.venv\lib\site-packages\eliottree\_render.py", line 264, in render_tasks
    for task in tasks:
  File "%userprofile%\.venv\lib\site-packages\eliottree\_parse.py", line 19, in tasks_from_iterable
    for message_dict in iterable:
  File "%userprofile%\.venv\lib\site-packages\toolz\functoolz.py", line 488, in __call__
    ret = f(ret)
  File "%userprofile%\.venv\lib\site-packages\eliottree\filter.py", line 47, in _filter
    return _parse_timestamp(task[u'timestamp']) < end_date
TypeError: 'bool' object is not subscriptable

I conda installed it from conda-forge (thank you for putting it there btw).
the eliot-tree version is '18.1.1'