Traceback (most recent call last):
  File "/usr/share/software-center/softwarecenter/backend/reviews.py", line 408, in _on_submit_review_data
    save_person_to_config(review.reviewer_username)
  File "/usr/share/software-center/softwarecenter/utils.py", line 460, in save_person_to_config
    UsefulnessCache(True)
  File "/usr/share/software-center/softwarecenter/backend/reviews.py", line 105, in __init__
    self._retrieve_votes_from_server()
  File "/usr/share/software-center/softwarecenter/backend/reviews.py", line 131, in _retrieve_votes_from_server
    spawn_helper.run(cmd)
  File "/usr/share/software-center/softwarecenter/backend/spawn_helper.py", line 67, in run
    standard_output=True, standard_error=True)
TypeError: gi._glib.spawn_async: first argument must be a sequence of strings