Can't save/upload the results. 'output_file' parameter lacking default value

[Enrico]

Checkbox doesn't save/upload the test results. Starting checkbox-gui from the terminal returns the following error when i try to save the results. If I try to upload the results, the gui returns a "could not read /tmp/submission.xml" error. I guess that the upload error is due to the saving error.

Error: QDBusError("org.freedesktop.DBus.Python.TypeError", "Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/dbus/service.py", line 707, in _message_cb
    retval = candidate_method(self, *args, **keywords)
  File "/usr/lib/python3/dist-packages/checkbox_ng/dbus_ex/decorators.py", line 231, in sanity
    return func(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/checkbox_ng/service.py", line 226, in wrapper
    bound = sig.bind(*args, **kwargs)
  File "/usr/lib/python3.4/inspect.py", line 2654, in bind
    return args[0]._bind(args[1:], kwargs)
  File "/usr/lib/python3.4/inspect.py", line 2573, in _bind
    raise TypeError(msg) from None
TypeError: 'output_file' parameter lacking default value
")

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: checkbox-gui 0.18-0ubuntu2
ProcVersionSignature: Ubuntu 4.1.0-3.3-generic 4.1.3
Uname: Linux 4.1.0-3-generic x86_64
ApportVersion: 2.18-0ubuntu9
Architecture: amd64
CurrentDesktop: Unity
Date: Sat Sep 5 09:14:15 2015
InstallationDate: Installed on 2015-09-04 (0 days ago)
InstallationMedia: Ubuntu 15.10 "Wily Werewolf" - Alpha amd64 (20150903)
SourcePackage: checkbox
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Jeff Lane  (bladernr)]

Checkbox was removed from Ubuntu installs and this is now out of scope.