Reimplements the :meth:`QLabel.enterEvent` method.

        :param event: QEvent.
        :type event: QEvent

def enterEvent(self, event):
        """
        Reimplements the :meth:`QLabel.enterEvent` method.

        :param event: QEvent.
        :type event: QEvent
        """

        if self.__checkable:
            not self.__checked and self.setPixmap(self.__hover_pixmap)
        else:
            self.setPixmap(self.__hover_pixmap)