updating to work on debian sid : RuntimeError: Data access methods are unsupported. Use normal Python attributes instead

mdupont@mdupont-Aspire-7750G:~/experiments/a11n/accerciser-mirror$ accerciser 
Traceback (most recent call last):
  File "/usr/bin/accerciser", line 50, in <module>
    accerciser.main()
  File "/usr/local/lib/python2.7/dist-packages/accerciser/__init__.py", line 35, in main
    main = Main()
  File "/usr/local/lib/python2.7/dist-packages/accerciser/accerciser.py", line 62, in __init__
    self.window = AccerciserMainWindow(self.node)
  File "/usr/local/lib/python2.7/dist-packages/accerciser/main_window.py", line 51, in __init__
    self._populateUI(node)
  File "/usr/local/lib/python2.7/dist-packages/accerciser/main_window.py", line 110, in _populateUI
    paned.set_data('last_position', paned.get_position())
  File "/usr/lib/python2.7/dist-packages/gi/overrides/GObject.py", line 590, in _unsupported_data_method
    raise RuntimeError('Data access methods are unsupported. '
RuntimeError: Data access methods are unsupported. Use normal Python attributes instead