pyside连接错误“RuntimeError：无法连接信号clicked（）”

from PySide.QtCore import *
from PySide.QtGui import *

import sys
import stackwid

class Dialog(QDialog,stackwid.Ui_Dialog):

    def __init__(self,parent = None):
        super(Dialog,self).__init__(parent)
        self.setupUi(self)


        self.camButton.clicked.connect(self.set())


    def set(self):

        self.stackedWidget.setCurrentIndex(1)


app = QApplication(sys.argv)
form = Dialog()
form.show()
app.exec_()
from PySide.QtCore import *
from PySide.QtGui i