继承 QObject and QDesignerTaskMenuExtension .
The QPyDesignerTaskMenuExtension class is provided to work around the fact that it is not possible for a Python class to derive from multiple Qt 类。
In order to add custom entries to Qt Designer's task menu you should implement a Python class derived from QPyDesignerTaskMenuExtension rather than one derived from QObject and QDesignerTaskMenuExtension .
parent argument, if not None, causes self to be owned by Qt instead of PyQt.