Saves the logging settings for this widget to XML format.
        
        :param      xml | <xml.etree.ElementTree.Element>

def saveXml(self, xml):
        """
        Saves the logging settings for this widget to XML format.
        
        :param      xml | <xml.etree.ElementTree.Element>
        """
        lvls = []
        for logger, level in self.loggerLevels().items():
            lvls.append('{0}:{1}'.format(logger, level))
        
        xlevels = ElementTree.SubElement(xml, 'levels')
        xlevels.text = ','.join(map(str, self.activeLevels()))
        
        xloggerlevels = ElementTree.SubElement(xml, 'logger_levels')
        xloggerlevels.text = ','.join(lvls)
        
        xml.set('filter', wrapVariant(self.uiFilterTXT.text()))
        
        xtree = ElementTree.SubElement(xml, 'tree')
        self.uiRecordTREE.saveXml(xtree)