#0  0xb76fc6c4 in g_logv (log_domain=0xb782fd8f "GLib-GObject", log_level=G_LOG_LEVEL_CRITICAL, 
    format=0xb777941c "%s: assertion `%s' failed", args1=0xbfffefdc "\017\r\203\267q\002\203\267") at gmessages.c:553
#1  0xb76fc767 in g_log (log_domain=0xb782fd8f "GLib-GObject", log_level=G_LOG_LEVEL_CRITICAL, 
    format=0xb777941c "%s: assertion `%s' failed") at gmessages.c:577
#2  0xb76fc7aa in g_return_if_fail_warning (log_domain=0xb782fd8f "GLib-GObject", pretty_function=0xb7830d0f "g_object_set_qdata", 
    expression=0xb7830271 "G_IS_OBJECT (object)") at gmessages.c:586
#3  0xb780aec1 in g_object_set_qdata (object=0x0, quark=60, data=0x1) at gobject.c:2829
#4  0xb764c6cf in pygobject_new_sunk (obj=0x0) at pygobject.c:994
#5  0xb7655e62 in pyg_value_as_pyobject (value=0xbffff1dc, copy_boxed=1) at pygtype.c:1143
#6  0xb7642bdc in pyg_object_set_property (object=0x8252060, property_id=1, value=0xbffff1dc, pspec=0x82b56c8)
    at gobjectmodule.c:268
#7  0xb78070ec in object_set_property (object=0x8252060, pspec=0x82b56c8, value=0xbffff288, nqueue=0x8252090) at gobject.c:1185
#8  0xb7808cce in g_object_set_property (object=0x8252060, property_name=0xb7bd5e8c "foo", value=0xbffff288) at gobject.c:1915
#9  0xb764b4f8 in set_property_from_pspec (obj=0x8252060, attr_name=0xb7bd5e8c "foo", pspec=0x82b56c8, pvalue=0xb7f987ac)
    at pygobject.c:360
#10 0xb764b67a in PyGProps_setattro (self=0x8228d4c, attr=0xb7bd5e78, pvalue=0xb7f987ac) at pygobject.c:409
#11 0xb7e96537 in PyObject_SetAttr () from /usr/lib/libpython2.7.so.1.0
#12 0xb7eefdde in PyEval_EvalFrameEx () from /usr/lib/libpython2.7.so.1.0
#13 0xb7ef47e2 in PyEval_EvalCodeEx () from /usr/lib/libpython2.7.so.1.0
#14 0xb7ef4953 in PyEval_EvalCode () from /usr/lib/libpython2.7.so.1.0
#15 0xb7f0e4bc in run_mod () from /usr/lib/libpython2.7.so.1.0
#16 0xb7f0f46d in PyRun_FileExFlags () from /usr/lib/libpython2.7.so.1.0
#17 0xb7f10019 in PyRun_SimpleFileExFlags () from /usr/lib/libpython2.7.so.1.0
#18 0xb7f10cdc in PyRun_AnyFileExFlags () from /usr/lib/libpython2.7.so.1.0
#19 0xb7f21d87 in Py_Main () from /usr/lib/libpython2.7.so.1.0
#20 0x080484e7 in main ()
