Keyword arguments:
            namespaceURI -- namespace of attribute to create, None is for
                attributes in no namespace.
            localName -- local name of new attribute
            value -- value of new attribute

def setAttributeNS(self, namespaceURI, localName, value):
        '''
        Keyword arguments:
            namespaceURI -- namespace of attribute to create, None is for
                attributes in no namespace.
            localName -- local name of new attribute
            value -- value of new attribute
        ''' 
        prefix = None
        if namespaceURI:
            try:
                prefix = self.getPrefix(namespaceURI)
            except KeyError, ex:
                prefix = 'ns2'
                self.setNamespaceAttribute(prefix, namespaceURI)
        qualifiedName = localName
        if prefix:
            qualifiedName = '%s:%s' %(prefix, localName)
        self._setAttributeNS(namespaceURI, qualifiedName, value)