PySide2 works not efficient - python-3.x

Question

from PySide2.QtWidgets import QApplication, QMainWindow,QDialog,QLineEdit,QPushButton
from PySide2.QtCore import Qt
import sys
from ui618 import Ui_MainWindow
from numpad import Ui_Dialog
class MyWindow:
def __init__(self) -> None:
self.lastSelectedEditLine = None
# main ui
self.MainWindow = QMainWindow()
self.ui = Ui_MainWindow()
self.ui.setupUi(self.MainWindow)
# numpad
self.QDialog = QDialog(self.MainWindow)
self.numpad = Ui_Dialog()
self.numpad.setupUi(self.QDialog)
self.QDialog.setWindowFlags(Qt.Popup)
# bind editline with numpad
self.lineEdits = self.MainWindow.findChildren(QLineEdit)
for item in self.lineEdits:
item.focusInEvent = lambda e,item=item:self.test(e,item)
def save_quit(self):
sys.exit()
def bindbtn(self):
self.ui.quit.clicked.connect(self.save_quit)
def numpad_btn(self,a,item):
if item.text() != '←':
self.lastSelectedEditLine.setText(self.lastSelectedEditLine.text()+item.text())
else:
self.lastSelectedEditLine.setText(self.lastSelectedEditLine.text()[:-1])
def bindNumpad(self):
numpad_btns = self.QDialog.findChildren(QPushButton)
for item in numpad_btns:
item.clicked.connect(lambda ignore='ignore',item=item : self.numpad_btn(ignore,item))
def test(self,e,item):
self.lastSelectedEditLine = item
this = item
x = self.MainWindow.x()
y = self.MainWindow.y() + self.ui.selectX.rect().bottom()
while this.parentWidget().objectName() != 'MainWindow':
x += this.x()
y += this.y()
this = this.parentWidget()
self.QDialog.move(x, y)
self.QDialog.show()
item.clearFocus()
def show(self):
self.MainWindow.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
myWindow = MyWindow()
myWindow.show()
myWindow.bindbtn()
myWindow.bindNumpad()
sys.exit(app.exec_())
The code works as expected, the numpad shows while focusing in a qlineedit. and can write and delete to target input line.
I am new to pyside2. Is there a better way to implement the numpad? I this way, the cursor is disable, I have to edit at the end of each editline.
It take several seconds while starting, Some one know how to improve it?