How to use the qtawesome.iconic_font.CharIconEngine function in QtAwesome

def __init__(self, iconic, painter, options):
        super(CharIconEngine, self).__init__()
        self.iconic = iconic
        self.painter = painter
        self.options = options

def _icon_by_painter(self, painter, options):
        """Return the icon corresponding to the given painter."""
        engine = CharIconEngine(self, painter, options)
        return QIcon(engine)

def _icon_by_painter(self, painter, options):
        """Return the icon corresponding to the given painter."""
        engine = CharIconEngine(self, painter, options)
        return QIcon(engine)

def __init__(self, iconic, painter, options):
        super(CharIconEngine, self).__init__()
        self.iconic = iconic
        self.painter = painter
        self.options = options