如何根据combobox里A选项，令label修改成C的内容？

class MainWindow(QMainWindow, Ui_MainWindow):
def __init__(self, parent=None):
super(MainWindow, self).__init__(parent)
self.setupUi(self)
self.comboBox = QtWidgets.QComboBox(self.centralWidget)
self.comboBox.setGeometry(QtCore.QRect(270, 220, 69, 22))
self.comboBox.setObjectName("comboBox")
self.comboBox.addItem("我想静静")
self.comboBox.addItem("我想123")
self.comboBox.addItem("我想56静")
self.comboBox.addItem("我想897")
self.label = QtWidgets.QLabel(self.centralWidget)
self.label.setGeometry(QtCore.QRect(320, 420, 69, 22))
self.label.setObjectName("label")
self.label.setText("")
k = self.comboBox.currentText
if k =='我想56静':
print('ok')
self.label.setText("111")
self.comboBox.currentTextChanged['QString'].connect(self.label.setText)
def m(self):
pass

大概代码这样

但是运行起来却无效