def _read_rule_set(path: str) -> RewriteRule:
    logging.info("reading rewrite rules from %r", path)
    # Below read call might throw IOError.
    lines = morphotactics_reader.read_rule_definitions(path)

    for index, line in lines.items():
      try:
        morphotactics_validator.validate(line)
      except morphotactics_validator.InvalidMorphotacticsRuleError as error:
        raise MorphotacticsCompilerError(
            f"Rewrite rule at line {index} of '{path}' is illformed. {error}")

    return morphotactics_parser.parse(list(lines.values()))
 def test_success(self, _, rule_definitions, expected_pbtxt):
     actual = parser.parse(rule_definitions)
     expected = rule_pb2.RewriteRuleSet()
     text_format.Parse(expected_pbtxt, expected)
     self.assertEqual(expected, actual)