AttributeError: 'ConversationEventListWalker' object has no attribute 'positions'

[jose1711]

If I hit End during browsing conversation history I am presented with:

Traceback (most recent call last):
  File "/usr/bin/hangups", line 33, in <module>
    sys.exit(load_entry_point('hangups==0.4.17', 'console_scripts', 'hangups')())
  File "/usr/lib/python3.10/site-packages/hangups/ui/__main__.py", line 1215, in main
    ChatUI(
  File "/usr/lib/python3.10/site-packages/hangups/ui/__main__.py", line 153, in __init__
    raise self._exception  # pylint: disable=raising-bad-type
  File "/usr/lib/python3.10/asyncio/events.py", line 80, in _run
    self._context.run(self._callback, *self._args)
  File "/usr/lib/python3.10/site-packages/urwid/raw_display.py", line 416, in <lambda>
    wrapper = lambda: self.parse_input(
  File "/usr/lib/python3.10/site-packages/urwid/raw_display.py", line 515, in parse_input
    callback(processed, processed_codes)
  File "/usr/lib/python3.10/site-packages/urwid/main_loop.py", line 412, in _update
    self.process_input(keys)
  File "/usr/lib/python3.10/site-packages/urwid/main_loop.py", line 513, in process_input
    k = self._topmost_widget.keypress(self.screen_size, k)
  File "/usr/lib/python3.10/site-packages/hangups/ui/__main__.py", line 1012, in keypress
    key = super().keypress(size, key)
  File "/usr/lib/python3.10/site-packages/hangups/ui/__main__.py", line 304, in keypress
    return super().keypress(size, key)
  File "/usr/lib/python3.10/site-packages/urwid/container.py", line 1626, in keypress
    key = self.focus.keypress(tsize, key)
  File "/usr/lib/python3.10/site-packages/urwid/container.py", line 1135, in keypress
    return self.body.keypress( (maxcol, remaining), key )
  File "/usr/lib/python3.10/site-packages/hangups/ui/__main__.py", line 923, in keypress
    return super().keypress(size, key)
  File "/usr/lib/python3.10/site-packages/hangups/ui/__main__.py", line 304, in keypress
    return super().keypress(size, key)
  File "/usr/lib/python3.10/site-packages/urwid/container.py", line 1626, in keypress
    key = self.focus.keypress(tsize, key)
  File "/usr/lib/python3.10/site-packages/hangups/ui/__main__.py", line 436, in keypress
    key = super().keypress(size, key)
  File "/usr/lib/python3.10/site-packages/hangups/ui/__main__.py", line 304, in keypress
    return super().keypress(size, key)
  File "/usr/lib/python3.10/site-packages/urwid/listbox.py", line 994, in keypress
    return actual_key(self._keypress_max_right((maxcol, maxrow)))
  File "/usr/lib/python3.10/site-packages/urwid/listbox.py", line 1004, in _keypress_max_right
    self.focus_position = next(iter(self.body.positions(reverse=True)))
AttributeError: 'ConversationEventListWalker' object has no attribute 'positions'

Arch Linux, x86_64, using latest snapshot from git

[tdryer]

Looks related to https://github.com/urwid/urwid/issues/318.