Jestem nowy w tym ... Zadzwoniłbym do funkcji "funcion" po kliknięciu "btn_brow_3" Jak mogłem to zrobić? Ktoś może mi pomóc?

Błąd TYPE ERROR Argument connect () slot powinien być wywoływalny lub sygnał nie „nonetype”

Pozdrawiam Maxi

import atexit
import sys
from PyQt4 import QtGui
import os                           # Libreria para manejar directorios del sistema operativo

def funcion(a):
    print "Hola mundo" + str(a)

class Example(QtGui.QMainWindow):

    def __init__(self):
        super(Example, self).__init__()

        self.initUI()

    def initUI(self):               

        exitAction = QtGui.QAction(QtGui.QIcon('c:/prueba gui/resource/logo.png'), 'Exit', self)
        exitAction.setShortcut('Ctrl+Q')
        exitAction.triggered.connect(QtGui.qApp.quit)

        btn_brow_1 = QtGui.QPushButton('Browser...', self)
        btn_brow_1.resize(btn_brow_1.sizeHint())
        btn_brow_1.move(300, 50)
        btn_brow_1.clicked.connect(self.showDialog_points)

        btn_brow_2 = QtGui.QPushButton('Dir browser', self)
        btn_brow_2.resize(btn_brow_2.sizeHint())
        btn_brow_2.move(300, 80)
        btn_brow_2.clicked.connect(self.showDialog_indir_stl)

        btn_brow_3 = QtGui.QPushButton('Dir browser', self)
        btn_brow_3.resize(btn_brow_3.sizeHint())
        btn_brow_3.move(300, 110)
        btn_brow_3.clicked.connect(self.showDialog_outdir_stl)




        btn_brow_4 = QtGui.QPushButton('Crear soportes', self)
        btn_brow_4.setGeometry(20, 145, 250, 25)
        #btn_brow_4.clicked.connect(support.main(fname_points, self.fname_stl_indir, self.fname_stl_outdir))
        btn_brow_4.clicked.connect(funcion(12))  # HERE IS THE PROBLEM!

        self.le1 = QtGui.QLineEdit(self)
        self.le1.setGeometry(20, 50, 250,21)

        self.le2 = QtGui.QLineEdit(self)
        self.le2.setGeometry(20, 80, 250,21)

        self.le3 = QtGui.QLineEdit(self)
        self.le3.setGeometry(20, 110, 250,21)

        self.statusBar().showMessage("Ready")

        self.toolbar = self.addToolBar('Exit')
        self.toolbar.addAction(exitAction)

        self.setGeometry(300, 300, 400, 200)
        self.setWindowTitle('Support from points generator')    
        self.show()



    def showDialog_points(self):

        self.fname_points = QtGui.QFileDialog.getOpenFileName(self, 'Open points file', '/home')
        self.statusBar().showMessage(str(self.fname_points))
        self.le1.setText(str(self.fname_points))
        self.fname_points = str(self.le1.text())
        print fname_points


    def showDialog_indir_stl(self):

        self.fname_stl_indir = QtGui.QFileDialog.getExistingDirectory(self, 'Select STL INPUT directory', '/home')
        self.statusBar().showMessage(str(self.fname_stl_indir))
        self.le2.setText(str(self.fname_stl_indir))
        self.fname_stl_indir = str(self.le2.text())
        print fname_stl_indir 

    def showDialog_outdir_stl(self):

        self.fname_stl_outdir = QtGui.QFileDialog.getExistingDirectory(self, 'Select STL OUTPUT directory', '/home')
        self.statusBar().showMessage(str(self.fname_stl_outdir))
        self.le3.setText(str(self.fname_stl_outdir))
        self.fname_stl_outdir = str(self.le3.text())
        print fname_stl_outdir 

def main():

    app = QtGui.QApplication(sys.argv)
    ex = Example()


    sys.exit(app.exec_())

if __name__ == '__main__':
    main()