[SOLUCIONADO] Funcion de boton PyQT4

from PyQt4 import QtCore, QtGui

try:
    _fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
    _fromUtf8 = lambda s: s

class Ui_cronometro(object):
    def setupUi(self, cronometro):
        cronometro.setObjectName(_fromUtf8("cronometro"))
        cronometro.resize(288, 57)
        cronometro.setWindowFlags(QtCore.Qt.FramelessWindowHint)
        self.gridLayoutWidget = QtGui.QWidget(cronometro)
        self.gridLayoutWidget.setGeometry(QtCore.QRect(10, 10, 272, 41))
        self.gridLayoutWidget.setObjectName(_fromUtf8("gridLayoutWidget"))
        self.gridLayout = QtGui.QGridLayout(self.gridLayoutWidget)
        self.gridLayout.setMargin(0)
        self.gridLayout.setObjectName(_fromUtf8("gridLayout"))
        self.lcdNumber = QtGui.QLCDNumber(self.gridLayoutWidget)
        self.lcdNumber.setProperty("intValue", 0)
        self.lcdNumber.setObjectName(_fromUtf8("lcdNumber"))
        self.gridLayout.addWidget(self.lcdNumber, 0, 0, 1, 1)
        self.label = QtGui.QLabel(self.gridLayoutWidget)
        self.label.setObjectName(_fromUtf8("label"))
        self.gridLayout.addWidget(self.label, 0, 1, 1, 1)
        self.toolButton = QtGui.QToolButton(self.gridLayoutWidget)
        self.toolButton.setObjectName(_fromUtf8("toolButton"))
        self.gridLayout.addWidget(self.toolButton, 0, 2, 1, 1)

        self.retranslateUi(cronometro)
        QtCore.QMetaObject.connectSlotsByName(cronometro)
        QtCore.QObject.connect(self.toolButton, QtCore.SIGNAL(_fromUtf8("clicked()")), cronometro.close)

    def retranslateUi(self, cronometro):
        cronometro.setWindowTitle(QtGui.QApplication.translate("cronometro", "Sesion", None, QtGui.QApplication.UnicodeUTF8))
        self.label.setText(QtGui.QApplication.translate("cronometro", "min restantes", None, QtGui.QApplication.UnicodeUTF8))
        self.toolButton.setText(QtGui.QApplication.translate("cronometro", "Cerrar Sesion", None, QtGui.QApplication.UnicodeUTF8))


if __name__ == "__main__":
    import sys
    app = QtGui.QApplication(sys.argv)
    cronometro = QtGui.QWidget()
    ui = Ui_cronometro()
    ui.setupUi(cronometro)
    cronometro.show()
    sys.exit(app.exec_())

class Tiempo(QtGui.QDialog):
	def __init__(self, parent=None):
		QtGui.QWidget.__init__(self, parent)
		self.timer = QtCore.QBasicTimer()
		self.c = Ui_cronometro()
		self.c.setupUi(self)
		QtCore.QObject.connect(self.c.toolButton, QtCore.SIGNAL(_fromUtf8("clicked()")), self.quit1) 
		self.step = 90
		self.h = int(self.step)/60
		self.m = int(self.step)%60
		self.codigo = None
		self.doAction()
		
	def doAction(self):
		self.timer.start(60000,self)
		
	def timerEvent(self, e):
		vent = VentanaPrincipal()
		if self.m > 0:
			self.m -= 1
			self.c.lcdNumber.display("%d:%d" % (self.h,self.m))
		else:
			self.m = 60
			self.h -= 1
			self.c.lcdNumber.display("%d:%d" % (self.h,self.m))
				
		if self.step == 10:
			vent.popup("Faltan "+str(self.step)+" minutos","le queda "+str(self.step)+"min de tiempo para estar en la sala, guarde todo ya que puede perder lo que ha hecho",1)
		if self.step == 3:
			vent.popup("Faltan "+str(self.step)+" minutos","le queda "+str(self.step)+"min de tiempo para estar en la sala, guarde todo ya que puede perder lo que ha hecho",3)
		if self.step == 0:
			self.quit1()
			return

		self.step = self.step - 1
		#~ self.c.lcdNumber.display(self.step)
		
	def quit1(self):
		self.timer.stop()
		........

def closeEvent(self, event):
        event.ignore()