def get_annotation_type(self, r_term):
for _, _, typ in self.graph.triples((<EOL>r_term, self.spdx_namespace['<STR_LIT>'], None)):<EOL><INDENT>if typ is not None:<EOL><INDENT>return typ<EOL><DEDENT>else:<EOL><INDENT>self.error = True<EOL>msg = '<STR_LIT>'<EOL>self.logger.log(msg)<EOL>return<EOL><DEDENT><DEDENT>
Returns annotation type or None if found none or more than one.
        Reports errors on failure.