docs: 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