Can't find the right function call from Py3DsMax (blur-dev) for selectionSetChanged

from blurdev.gui import Dialog
from Py3dsMax import mxs
import sys
from PyQt4 import QtGui,QtCore
from PyQt4.QtCore import QSignalMapper, pyqtSignal
from PyQt4.QtGui import QPalette
 
class callBack:
    def selCallBack(self):
            print "selCallBack!"
 
class sceneExplorer(Dialog):
    def __init__(self, parent = None):
        super(sceneExplorer, self).__init__()
        self.initUI()
 
    def initUI(self):
        self.last_sel_index = -1
        self.setWindowTitle('Scene Explorer')
        mxs.callbacks.addScript(mxs.pyhelper.namify("selectionSetChanged"), "python.exec('test = callBack()\ntest.selCallBack()\n')", id = mxs.pyhelper.namify("scene_explorer"))
        QtGui.QToolTip.setFont(QtGui.QFont('SansSerif', 10))
        self.horizontalLayout = QtGui.QGridLayout(self)
        self.scrollArea = QtGui.QScrollArea(self)
        self.scrollArea.setWidgetResizable(True)
        self.scrollAreaWidgetContents = Dialog()
        self.scrollAreaWidgetContents.setGeometry(QtCore.QRect(0, 0, 380, 280))
        self.horizontalLayout_2 = QtGui.QHBoxLayout(self.scrollAreaWidgetContents)
        self.gridLayout = QtGui.QGridLayout()
        self.gridLayout.setSpacing(0)
        self.horizontalLayout_2.addLayout(self.gridLayout)
        self.scrollArea.setWidget(self.scrollAreaWidgetContents)
        self.add_button = QtGui.QPushButton("Refresh Explorer")
        self.center_button = QtGui.QPushButton("Center Window")
        self.horizontalLayout.addWidget(self.scrollArea, 1, 0)
        self.horizontalLayout.addWidget(self.add_button, 0, 0)
        self.horizontalLayout.addWidget(self.center_button, 0, 1)
        self.connect(self.add_button, QtCore.SIGNAL("clicked()"), self.addButtons)
        self.connect(self.center_button, QtCore.SIGNAL("clicked()"), self.center)
        self.setGeometry(300, 200, 400, 300)
 
    def addChildren (self, button_index, obj, row):
        signalMapper = QSignalMapper(self)
        for child in obj.Children:
            button_index = button_index + 1
            if len(child.Children):
                self.expand_button = QtGui.QPushButton("-")
            else:
                self.expand_button = QtGui.QPushButton(" ")
            self.expand_button.setSizePolicy(QtGui.QSizePolicy(QtGui.QSizePolicy.Fixed,QtGui.QSizePolicy.Fixed))
            self.expand_button.setMaximumSize(10,10)
            self.child_button = QtGui.QPushButton(child.name)
            self.child_button.setSizePolicy(QtGui.QSizePolicy(QtGui.QSizePolicy.Minimum,QtGui.QSizePolicy.Fixed))
            self.child_button.setMaximumSize(10000,16)
            self.child_button.setToolTip(child.name)
            self.gridLayout.addWidget(self.expand_button, button_index, row)
            self.gridLayout.addWidget(self.child_button, button_index, row + 1)
            self.child_button.setAutoFillBackground(True)
            self.all_buttons.append(self.child_button) # a collection of all buttons
            self.all_max_obj.append(child) # a collection of the max objects
            signalMapper.setMapping(self.child_button, button_index) # map a value to the button
            self.child_button.clicked.connect(signalMapper.map) #connect to signalMapper
            button_index = self.addChildren(button_index, child, row + 2)
        signalMapper.mapped.connect(self.highlightButton) #connect signalMapper to highlightButton
        return button_index
 
    def addButtons(self):
        self.all_buttons = []
        self.all_max_obj = []
        highlightButton = pyqtSignal(int)
        signalMapper = QSignalMapper(self)
        button_index = 0
        for obj in mxs.objects:
            if obj.Parent == None:
                if len(obj.Children):
                    self.expand_button = QtGui.QPushButton("-")
                else:
                    self.expand_button = QtGui.QPushButton(" ")
                self.expand_button.setSizePolicy(QtGui.QSizePolicy(QtGui.QSizePolicy.Fixed,QtGui.QSizePolicy.Fixed))
                self.expand_button.setMaximumSize(10,10)
                self.obj_button = QtGui.QPushButton(obj.name)
                self.obj_button.setSizePolicy(QtGui.QSizePolicy(QtGui.QSizePolicy.Minimum,QtGui.QSizePolicy.Fixed))
                self.obj_button.setMaximumSize(10000,16)
                self.obj_button.setToolTip(obj.name)
                self.gridLayout.addWidget(self.expand_button, button_index, 0)
                self.gridLayout.addWidget(self.obj_button, button_index, 1)
                self.obj_button.setAutoFillBackground(True)
                self.all_buttons.append(self.obj_button) # a collection of all buttons
                self.all_max_obj.append(obj) # a collection of the max objects
                signalMapper.setMapping(self.obj_button, button_index) # map a value to the button
                self.obj_button.clicked.connect(signalMapper.map) #connect to signalMapper
                button_index = self.addChildren(button_index, obj, 2)
                button_index = button_index + 1
        signalMapper.mapped.connect(self.highlightButton) #connect signalMapper to highlightButton
 
    def highlightButton(self,index):
        palette = QPalette()
        if self.last_sel_index != -1:
            self.color = QtGui.QColor(215, 215, 215)
            palette.setColor(QPalette.Button, self.color)
            self.all_buttons[self.last_sel_index].setPalette(palette) # remove highlight
        actual_color = self.all_buttons[index].palette().color(1) #sample actual_color
        if actual_color == QtGui.QColor(255, 127, 127):
            self.color = QtGui.QColor(215, 215, 215)
        else:
            self.color = QtGui.QColor(255, 127, 127)
        palette.setColor(QPalette.Button, self.color)
        self.all_buttons[index].setPalette(palette) # apply new color
        self.selectObject(index)
        self.last_sel_index = index
 
    def selectObject(self, index):
        try:
            mxs.select (self.all_max_obj[index])
        except IOError:
            mxs.select (None)
 
    def center(self):
        qr = self.frameGeometry()
        cp = QtGui.QDesktopWidget().availableGeometry().center()
        qr.moveCenter(cp)
        self.move(qr.topLeft())
 
    def selCallBack(self):
        print "selCallBack!"
 
def main():
   import blurdev 
   blurdev.launch(sceneExplorer)
 
if __name__ == '__main__':
    main()