'Renders an annotation element for HTML output.'

def _render_annotation(self, index, el):

    attr = {}
    attr.update(self._get_annotation_class_attr(index, el))
    attr.update(self._get_annotation_data_attr(index, el))
    el.tag = 'span'
    for key in attr.keys():
        el.set(key, attr[key]['value'])
        if (('_delete' in attr[key]) and (attr[key]['_delete'] is not None)):
            delete_key = attr[key]['_delete']
            del el.attrib[delete_key]
