---

import sys, PyQt6
from PyQt6.QtWidgets import QApplication, QDialog
from PyQt6.uic import loadUi

class Dialog(QDialog):
    def __init__(self):
        super().__init__()
        loadUi('CheckDemo.ui', self)
        self.setWindowTitle('Окно авторизации')
        self.setGeometry(200,200,700,400)

        # connect to signal
        self.checkBox_pizza.stateChanged.connect(self.check_selected)
        self.checkBox_salad.stateChanged.connect(self.check_selected)
        self.checkBox_sausage.stateChanged.connect(self.check_selected)

    def check_selected(self):
        price = 10

        if self.checkBox_pizza.isChecked():
            price = price + 3
        if self.checkBox_salad.isChecked():
            price = price + 4
        if self.checkBox_sausage.isChecked():
            price = price + 5
        self.label_result.setText("Total Price Is : {} ".format(price))


if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = Dialog()
    window.show()
    sys.exit(app.exec())