QLineEdit 按键Tab键时 显示历史记录

#LineEdit添加历史记录功能，按下回车添加至历史中
class LineEditWithHistory(QtWidgets.QLineEdit):
    def __init__(self, parent ,inputList=[]):
        super(LineEditWithHistory, self).__init__(parent)

        #用于存放历史记录的List
        self.inputList = inputList
        #LineEdit设置QCompleter，用于显示历史记录
        self.completer = QtWidgets.QCompleter(self)
        self.listModel = QtCore.QStringListModel(self.inputList, self)
        self.completer.setCaseSensitivity(QtCore.Qt.CaseInsensitive)
        self.completer.setModel(self.listModel)
        self.completer.activated.connect(self.Slot_completer_activated)
        self.setCompleter(self.completer)
        #输入完成按下回车后去重添加到历史记录中
        self.returnPressed.connect(self.Slot_editingFinished)

    def Slot_editingFinished(self):
        content = self.text()
        if content != "":
            if content not in self.inputList:
                self.inputList.append(content)
                self.listModel.setStringList(self.inputList)
                self.completer.setCompletionMode(QtWidgets.QCompleter.PopupCompletion)

    #按下回车后恢复显示模式  https://doc.qt.io/qt-5/qcompleter.html#activated
    def Slot_completer_activated(self,text):
        self.completer.setCompletionMode(QtWidgets.QCompleter.PopupCompletion)

    def event(self, event):
        #按下Tab键时弹出所有记录
        if event.type() == QtCore.QEvent.KeyPress and event.key() == QtCore.Qt.Key_Tab:
            #设置不过滤显示  https://doc.qt.io/qt-5/qcompleter.html#completionMode-prop
            self.completer.setCompletionMode(QtWidgets.QCompleter.UnfilteredPopupCompletion)
            self.completer.complete()
            self.completer.popup().show()
            return True
        return super().event(event)