My XBMC AddOn produces a lot of log warnings about potential memory leaks:
13:49:02 T:139712465467136 WARNING: CPythonInvoker(12, /home/test/.xbmc/addons/script.testplugin/default.py): the python script "/home/test/.xbmc/addons/script.testplugin/default.py" has left several classes in memory that we couldn't clean up. The classes include: N14PythonBindings42XBMCAddon_xbmcgui_WindowXMLDialog_DirectorE,N9XBMCAddon7xbmcgui12ControlLabelE,N9XBMCAddon7xbmcgui12ControlLabelE,N9XBMCAddon7xbmcgui8ListItemE
What causes this warnings and how can I avoid them?