QtCore connectSlotsByName, 无其他connect函数，但是仍然每次被激活2次

#!/usr/bin/env python
# coding: utf-8

import sys
from PyQt5.QtWidgets import QApplication,QMainWindow,QWidget
from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(432, 243)
        self.gridLayoutWidget = QtWidgets.QWidget(Form)
        self.gridLayoutWidget.setGeometry(QtCore.QRect(10, 60, 411, 171))
        self.pushButton = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton.setObjectName("pushButton")
        self.gridLayout = QtWidgets.QGridLayout(self.gridLayoutWidget)
        self.gridLayout.addWidget(self.pushButton, 4, 0, 1, 1)

        self.retranslateUi(Form)

        QtCore.QMetaObject.connectSlotsByName(Form)

        #self.pushButton.clicked.connect(MyForm.showit)

    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))
        self.pushButton.setText(_translate("Form", "Add Slots"))

class MyForm(QMainWindow,Ui_Form):
    def __init__(self):
        super(MyForm, self).__init__()
        self.setupUi(self)

采用connectSlotsByName，用cliecked命名，如下就总是运行2次

    #@QtCore.pyqtSignature("")
    def on_pushButton_clicked(self):
        print ("A")

    @staticmethod
    def showit(self):
        print ("B")

app = QApplication(sys.argv)
a = MyForm()
a.show()
app.exec()