code: def setOnPixmap(self, pixmap):
          
          pmap = QtGui.QPixmap(pixmap)
          self._onPixmap = pmap.scaled(self.width(), self.height(),
                                       QtCore.Qt.KeepAspectRatio,
                                       QtCore.Qt.SmoothTransformation)
docs: Sets the on pixmap that will be used for this button to the given
          pixmap.  THis can be a QPixmap instance, or a string for where to load
          the pixmap from.
          
          :param      pixmap | <QtGui.QPixmap> || <str>