def add_highlight(self, field, fragment_size=None,<EOL>number_of_fragments=None, fragment_offset=None, type=None):
if self._highlight is None:<EOL><INDENT>self._highlight = HighLighter("<STR_LIT>", "<STR_LIT>")<EOL><DEDENT>self._highlight.add_field(field, fragment_size, number_of_fragments, fragment_offset, type=type)<EOL>return self<EOL>
Add a highlight field.

        The Search object will be returned, so calls to this can be chained.