Returns the label that is used for drawing the rich text to this button.
        
        :return     <QLabel>

def richTextLabel(self):
        """
        Returns the label that is used for drawing the rich text to this button.
        
        :return     <QLabel>
        """
        if not self._richTextLabel:
            self._richTextLabel = QLabel(self)
            self._richTextLabel.installEventFilter(self)
            self._richTextLabel.setMargin(10)
        return self._richTextLabel