Apply stylesheet effect to menus of a qmenubar

I would like to know how I can apply a stylesheet effect to the menu buttons of a qmenubar in pyqt

this is the code to change the properties of the QMenuBar:

QMenuBar{

 background-color: rgb(49,49,49);
 color: rgb(255,255,255);
 border: 1px solid #000;
}

but when trying to apply the effect to one of the buttons of the qmenubar (inio-sales)

the effect does not apply.

I hope you can help me