按下按钮时如何调用自定义功能

Question

我刚接触Python ...我想使用signal connect()来调用自定义函数。我单击了按钮，但没有清除lineEdit。

我将self.pushButton.clicked.connect(self.lineEditChangeClear)更改为self.pushButton.clicked.connect(self.lineEdit.clear)，并且可以使用。你能告诉我区别吗？

from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(800, 600)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(480, 120, 75, 23))
        self.pushButton.setObjectName("pushButton")
        self.lineEdit = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit.setGeometry(QtCore.QRect(260, 120, 113, 20))
        self.lineEdit.setObjectName("lineEdit")
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 21))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        self.pushButton.clicked.connect(self.lineEditChangeClear)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)
        MainWindow.show()

    def lineEditChangeClear(self):
        self.lineEdit.clear()

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.pushButton.setText(_translate("MainWindow", "PushButton"))

if __name__ == "__main__":
    import sys
    app = QApplication(sys.argv)
    window = QMainWindow(None)
    Ui_MainWindow().setupUi(window)
    sys.exit(app.exec_())
    pass