'Return element XML based on attribute settings'

def xml(self, indent=0):

    indent_str = (u'    ' * indent)
    if self._is_empty:
        xml = (u'%s%s\n' % (indent_str, self._empty_element_tag))
    else:
        xml = (u'%s\n' % self._non_empty_element_xml(indent))
    return xml
