Saves the color set information out to string format.  The data is \
        returned as xml data.
        
        :return     <str>

def toString( self ):
        """
        Saves the color set information out to string format.  The data is \
        returned as xml data.
        
        :return     <str>
        """
        # convert the element tree information
        from xml.etree import ElementTree
        
        xelem = ElementTree.Element('colorset')
        xelem.set('name', self.name())
        xelem.set('colorGroups', ','.join(self.colorGroups()))
        
        for colorName, colors in self._colors.items():
            xcolor = ElementTree.SubElement(xelem, 'color')
            xcolor.set('name', colorName)
            
            for colorGroup, color in colors.items():
                xcolorval = ElementTree.SubElement(xcolor, 'value')
                xcolorval.set('group', colorGroup)
                xcolorval.set('red',    str(color.red()))
                xcolorval.set('green',  str(color.green()))
                xcolorval.set('blue',   str(color.blue()))
                xcolorval.set('alpha',  str(color.alpha()))
        
        # save the text
        return ElementTree.tostring(xelem)