def get_review_date(self, r_term):
reviewed_list = list(self.graph.triples((r_term, self.spdx_namespace['<STR_LIT>'], None)))<EOL>if len(reviewed_list) != <NUM_LIT:1>:<EOL><INDENT>self.error = True<EOL>msg = '<STR_LIT>'<EOL>self.logger.log(msg)<EOL>return<EOL><DEDENT>return six.text_type(reviewed_list[<NUM_LIT:0>][<NUM_LIT:2>])<EOL>
Returns review date or None if not found.
        Reports error on failure.
        Note does not check value format.