How to use the flexmock.InvalidExceptionMessage function in flexmock

if expectation.return_values:
        raised, instance = sys.exc_info()[:2]
        message = '%s' % instance
        expected = expectation.return_values[0].raises
        if not expected:
          raise
        args = expectation.return_values[0].value
        expected_instance = expected(*args['kargs'], **args['kwargs'])
        expected_message = '%s' % expected_instance
        if inspect.isclass(expected):
          if expected is not raised and expected not in raised.__bases__:
            raise (InvalidExceptionClass('expected %s, raised %s' %
                   (expected, raised)))
          if args['kargs'] and '_sre.SRE_Pattern' in str(args['kargs'][0]):
            if not args['kargs'][0].search(message):
              raise (InvalidExceptionMessage('expected /%s/, raised "%s"' %
                     (args['kargs'][0].pattern, message)))
          elif expected_message and expected_message != message:
            raise (InvalidExceptionMessage('expected "%s", raised "%s"' %
                   (expected_message, message)))
        elif expected is not raised:
          raise (InvalidExceptionClass('expected "%s", raised "%s"' %
                 (expected, raised)))

expected = expectation.return_values[0].raises
        if not expected:
          raise
        args = expectation.return_values[0].value
        expected_instance = expected(*args['kargs'], **args['kwargs'])
        expected_message = '%s' % expected_instance
        if inspect.isclass(expected):
          if expected is not raised and expected not in raised.__bases__:
            raise (InvalidExceptionClass('expected %s, raised %s' %
                   (expected, raised)))
          if args['kargs'] and '_sre.SRE_Pattern' in str(args['kargs'][0]):
            if not args['kargs'][0].search(message):
              raise (InvalidExceptionMessage('expected /%s/, raised "%s"' %
                     (args['kargs'][0].pattern, message)))
          elif expected_message and expected_message != message:
            raise (InvalidExceptionMessage('expected "%s", raised "%s"' %
                   (expected_message, message)))
        elif expected is not raised:
          raise (InvalidExceptionClass('expected "%s", raised "%s"' %
                 (expected, raised)))