Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/typecatcher/TypeCatcherWindow.py", line 197, in on_select_changed
    self.font = model[iter][0]
  File "/usr/lib/python2.7/dist-packages/gi/overrides/Gtk.py", line 767, in __getitem__
    aiter = self._getiter(key)
  File "/usr/lib/python2.7/dist-packages/gi/overrides/Gtk.py", line 755, in _getiter
    aiter = self.get_iter(key)
  File "/usr/lib/python2.7/dist-packages/gi/overrides/Gtk.py", line 789, in get_iter
    path = self._coerce_path(path)
  File "/usr/lib/python2.7/dist-packages/gi/overrides/Gtk.py", line 764, in _coerce_path
    return TreePath(path)
  File "/usr/lib/python2.7/dist-packages/gi/overrides/Gtk.py", line 1114, in __new__
    path = ":".join(str(val) for val in path)
TypeError: 'NoneType' object is not iterable