继承 QObject and QDesignerPropertySheetExtension .
The QPyDesignerPropertySheetExtension 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 manipulate a widget's properties you should implement a Python class derived from QPyDesignerPropertySheetExtension rather than one derived from QObject and QDesignerPropertySheetExtension .
parent argument, if not None, causes self to be owned by Qt instead of PyQt.