如何在pyqt5中使用connect从另一个类调用方法

我试图创建一个简单的gui应用程序,其结构如下

class MainWindow(QMainWindow):

def __init__(self):
    super().__init__()
    self.init_ui()

def init_ui(self):
    self.table_widget = MainTabWindow()
    self.setCentralWidget(self.table_widget)
    self.show()



class MainTabWindow(QTabWidget):

def __init__(self,parent=None):
    #super(QWidget, self).__init__(parent)
    super(MainTabWindow, self).__init__(parent)
    self.init_ui()

def init_ui(self):
    self.setWindowTitle('PyQt5 Tab Example')

    self.layout = QVBoxLayout(self)
    #self.selected_date = QDate.currentDate()
    #self.tabs = QTabWidget()
    self.tab1 = QWidget()
    self.tab2 = QWidget()
    self.tab3 = QWidget()
    self.tab4 = QWidget()
    #self.buttonLayout = QMainWindow()

    self.addTab(self.tab1,"Search")
    self.addTab(self.tab2,"Add/Update")
    self.addTab(self.tab3,"Billing Summary")
    self.addTab(self.tab4,"Search2")

    self.SearchTab()
    self.PGCreationTab()
    self.BillingSummaryTab()

def PGCreationTab(self):
  layout = QFormLayout()
  policy = QSizePolicy()
  layout.setFieldGrowthPolicy(QFormLayout.FieldGrowthPolicy(2))
  PG_obj = PGDetails()
  fn = PG_obj.setFirstName()
  layout.addRow("FirstName",fn)
  fn.textChanged.connect(PG_obj.getText)

def main():
    application = QApplication(sys.argv)
    main_window = MainTabWindow()
    main_window.show()
    sys.exit(application.exec_())

if __name__ == '__main__':
    main()

pgdetails类-

class PGDetails():

def __init__(self,parent=None):
    self.obj = 5
    #self.FirstName = QLineEdit()
    #self.FirstName.setValidator(QIntValidator())

def setFirstName(self):
    self.FirstName = QLineEdit()
    #print("Inside")
    #print(self.FirstName.text())
    return self.FirstName

def getText(self):
    print("Inside")
    print(self.FirstName.text())

我无法检查名字行框中的任何文本更改,gettext函数永远不会被调用。

如果我使用self,它会抛出一个错误,因为在maintabwindow中没有定义gettext

如何从maintabwindow类内部调用gettext函数