属性错误：“Ui”对象没有属性“ui”；

Question

我在从主窗口引用第二个窗口中的小部件时遇到问题。我试图在计算器功能中从 FN5 窗口引用我的小部件，然后在主窗口中引用该功能。现在我只有标签参考并尝试更改它所说的内容作为测试，但每次我尝试时都会收到 Ui AttributeError

class Ui(QMainWindow):
    def FN5(self):
        self.window = QMainWindow()
        self.ui = Ui_Fin5Window()
        self.ui.setupUi(self.window)
        self.window.show()

    def ChooseLine(self):
        SD1 = ["FN5"]
        SD2 = ["FN1", "FN2", "FN3", "FN4"]
        PS1 = ["FN6", "FN7", "FN8", "FN9", "FN10"]
        if SD1.count(self.Line_combobox.currentText()):
            self.start.clicked.connect(self.FN5)
        if SD2.count(self.Line_combobox.currentText()):
            self.start.clicked.connect(self.Retail)
        if PS1.count(self.Line_combobox.currentText()):
            self.start.clicked.connect(self.PS)

   def HourlyCalculator(self):
    
        self.Hourly = self.ui.Label_Hourly_Production
        self.Hourly.setText("Hourly")

    def __init__(self):
        super(Ui, self).__init__()

        uic.loadUi("Finishing.ui", self)

        self.start = self.findChild(QPushButton, "Start")

        self.start.clicked.connect(self.ChooseLine)
        self.start.clicked.connect(self.HourlyCalculator)