Internal Server Error: /c/matura3bc-staly/admin/contests/submission/
Traceback (most recent call last):
  File "/home/users/sio2/sio2/venv/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 132, in get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/users/sio2/sio2/venv/local/lib/python2.7/site-packages/django/utils/decorators.py", line 145, in inner
    return func(*args, **kwargs)
  File "/home/users/sio2/sio2/venv/local/lib/python2.7/site-packages/django/contrib/admin/options.py", line 618, in wrapper
    return self.admin_site.admin_view(view)(*args, **kwargs)
  File "/home/users/sio2/sio2/venv/local/lib/python2.7/site-packages/django/utils/decorators.py", line 110, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/home/users/sio2/sio2/venv/local/lib/python2.7/site-packages/django/views/decorators/cache.py", line 57, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "/home/users/sio2/sio2/venv/local/lib/python2.7/site-packages/django/contrib/admin/sites.py", line 233, in inner
    return view(request, *args, **kwargs)
  File "/home/users/sio2/sio2/venv/local/lib/python2.7/site-packages/django/utils/decorators.py", line 34, in _wrapper
    return bound_func(*args, **kwargs)
  File "/home/users/sio2/sio2/venv/local/lib/python2.7/site-packages/django/utils/decorators.py", line 110, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/home/users/sio2/sio2/venv/local/lib/python2.7/site-packages/django/utils/decorators.py", line 30, in bound_func
    return func.__get__(self, type(self))(*args2, **kwargs2)
  File "/home/users/sio2/sio2/venv/local/lib/python2.7/site-packages/django/contrib/admin/options.py", line 1592, in changelist_view
    response = self.response_action(request, queryset=cl.get_queryset(request))
  File "/home/users/sio2/sio2/venv/local/lib/python2.7/site-packages/django/contrib/admin/options.py", line 1335, in response_action
    response = func(self, request, queryset)
  File "/home/users/sio2/sio2/venv/src/oioioi/oioioi/base/admin.py", line 148, in delete_selected
    collect_deleted_objects(modeladmin, request, queryset)
  File "/home/users/sio2/sio2/venv/src/oioioi/oioioi/base/admin.py", line 240, in collect_deleted_objects
    to_delete = collector.nested(format_callback)
  File "/home/users/sio2/sio2/venv/local/lib/python2.7/site-packages/django/contrib/admin/utils.py", line 213, in nested
    roots.extend(self._nested(root, seen, format_callback))
  File "/home/users/sio2/sio2/venv/local/lib/python2.7/site-packages/django/contrib/admin/utils.py", line 198, in _nested
    ret = [format_callback(obj)]
  File "/home/users/sio2/sio2/venv/src/oioioi/oioioi/base/admin.py", line 237, in format_callback
    force_text(obj))
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc5 in position 2: ordinal not in range(128)

<WSGIRequest
path:/c/matura3bc-staly/admin/contests/submission/,
GET:<QueryDict: {u'user': [u'3922']}>,
POST:<QueryDict: {u'action': [u'delete_selected'], u'_selected_action': [u'297076', u'297074'], u'csrfmiddlewaretoken': [u'hefqQaJBvHr1YEhaa3XHNzMAUQcAe4ii'], u'select_across': [u'0']}>,