Error after creating invoice group

Internal Server Error: /app/tezor/client/1/invoice_groups/create/
Traceback (most recent call last):
  File "/srv/www/aleksis/venv/lib/python3.11/site-packages/django/core/handlers/exception.py", line 47, in inner
    response = get_response(request)
               ^^^^^^^^^^^^^^^^^^^^^
  File "/srv/www/aleksis/venv/lib/python3.11/site-packages/django/core/handlers/base.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/srv/www/aleksis/venv/lib/python3.11/site-packages/django/views/generic/base.py", line 70, in view
    return self.dispatch(request, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/srv/www/aleksis/venv/lib/python3.11/site-packages/django/utils/decorators.py", line 43, in _wrapper
    return bound_method(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/srv/www/aleksis/venv/lib/python3.11/site-packages/django/views/decorators/cache.py", line 44, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/srv/www/aleksis/venv/lib/python3.11/site-packages/django/contrib/auth/mixins.py", line 104, in dispatch
    return super().dispatch(request, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/srv/www/aleksis/venv/lib/python3.11/site-packages/django/views/generic/base.py", line 98, in dispatch
    return handler(request, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/srv/www/aleksis/venv/lib/python3.11/site-packages/django/views/generic/edit.py", line 172, in post
    return super().post(request, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/srv/www/aleksis/venv/lib/python3.11/site-packages/django/views/generic/edit.py", line 142, in post
    return self.form_valid(form)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/AlekSIS-App-Tezor/aleksis/apps/tezor/views.py", line 200, in form_valid
    return super().form_valid(form)
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/AlekSIS/aleksis/core/mixins.py", line 465, in form_valid
    return super().form_valid(form)
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/srv/www/aleksis/venv/lib/python3.11/site-packages/django/views/generic/edit.py", line 126, in form_valid
    return super().form_valid(form)
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/srv/www/aleksis/venv/lib/python3.11/site-packages/django/views/generic/edit.py", line 57, in form_valid
    return HttpResponseRedirect(self.get_success_url())
                                ^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/AlekSIS-App-Tezor/aleksis/apps/tezor/views.py", line 203, in get_success_url
    return reverse("client_by_pk", args=[self.object.client.pk])
                                         ^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'pk'

changed title from Unable to create client to Error after creating invoice group

mentioned in merge request !27 (merged)

mentioned in commit 85911898

closed with merge request !27 (merged)