a dead end: TypeError: Viewer.__init_subclass__() takes no keyword arguments

[freedomsha]

I reach a dead end:

08:21:52: Debug: Adding duplicate image handler for 'Windows bitmap file'
08:21:52: Debug: Adding duplicate animation handler for '1' type
08:21:52: Debug: Adding duplicate animation handler for '2' type
08:21:52: Debug: Adding duplicate image handler for 'Windows bitmap file'
08:21:52: Debug: Adding duplicate animation handler for '1' type
08:21:52: Debug: Adding duplicate animation handler for '2' type
Traceback (most recent call last):
File "/usr/share/pycharm/plugins/python-ce/helpers/pydev/pydevd.py", line 2252, in
main()
File "/usr/share/pycharm/plugins/python-ce/helpers/pydev/pydevd.py", line 2234, in main
globals = debugger.run(setup['file'], None, None, is_module)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/share/pycharm/plugins/python-ce/helpers/pydev/pydevd.py", line 1544, in run
return self._exec(is_module, entry_point_fn, module_name, file, globals, locals)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/share/pycharm/plugins/python-ce/helpers/pydev/pydevd.py", line 1551, in _exec
pydev_imports.execfile(file, globals, locals) # execute the script
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/share/pycharm/plugins/python-ce/helpers/pydev/_pydev_imps/pydev_execfile.py", line 18, in execfile
exec(compile(contents+"\n", file, 'exec'), glob, loc)
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoach.py", line 145, in
start()
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoach.py", line 132, in start
app = application.Application(
^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoachlib/patterns/singleton.py", line 28, in call
class.instance = super().call(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoachlib/application/application.py", line 255, in init
self.init(**kwargs)
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoachlib/application/application.py", line 445, in init
from taskcoachlib import gui, persistence
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoachlib/gui/init.py", line 23, in
from .mainwindow import MainWindow
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoachlib/gui/mainwindow.py", line 25, in
from . import artprovider, idlecontroller, remindercontroller, toolbar, uicommand, windowdimensionstracker
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoachlib/gui/remindercontroller.py", line 22, in
from taskcoachlib.gui.dialog.editor import TaskEditor
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoachlib/gui/dialog/init.py", line 21, in
from taskcoachlib.gui.dialog import editor
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoachlib/gui/dialog/editor.py", line 29, in
import taskcoachlib.gui.viewer.effort
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoachlib/gui/viewer/init.py", line 21, in
from .attachment import AttachmentViewer # ?
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoachlib/gui/viewer/attachment.py", line 32, in
from . import base, mixin
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoachlib/gui/viewer/base.py", line 60, in
class Viewer(wx.Panel, patterns.Observer, metaclass=PreViewer):
File "/home/sylvain/Téléchargements/src/TaskCoach-future2/taskcoach-repo-bb769bdee43327761e5f6fa7bbb7c3231b9376ac/taskcoach/taskcoachlib/patterns/metaclass.py", line 111, in call
instance = super().call(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: Viewer.init_subclass() takes no keyword arguments

Process finished with exit code 139 (interrupted by signal 11:SIGSEGV)