Sets the pixmap associated with this node.
        
        :param     pixmap | <str> || <QtGui.QPixmap> || None

def setPixmap(self, pixmap):
        """
        Sets the pixmap associated with this node.
        
        :param     pixmap | <str> || <QtGui.QPixmap> || None
        """
        if pixmap is not None:
            self._style = XNode.NodeStyle.Pixmap
            self._pixmap = QPixmap(pixmap)
        else:
            self._style = XNode.NodeStyle.Rectangle
            self._pixmap = pixmap
        
        self.update()