How to use the mrjob.parse.parse_s3_uri function in mrjob

cluster.status.statechangereason.message = (
                        'Shut down as step failed')

                return

            # complete step
            step.status.state = 'COMPLETED'
            step.status.timeline.enddatetime = to_iso8601(now)

            # create fake output if we're supposed to write to S3
            output_uri = self._get_step_output_uri(step.config.args)
            if output_uri and is_s3_uri(output_uri):
                mock_output = self.mock_emr_output.get(
                    (cluster_id, step_num)) or [b'']

                bucket_name, key_name = parse_s3_uri(output_uri)

                # write output to S3
                for i, part in enumerate(mock_output):
                    add_mock_s3_data(self.mock_s3_fs, {
                        bucket_name: {key_name + 'part-%05d' % i: part}})
            elif (cluster_id, step_num) in self.mock_emr_output:
                raise AssertionError(
                    "can't use output for cluster ID %s, step %d "
                    "(it doesn't output to S3)" %
                    (cluster_id, step_num))

            # done!
            # if this is the last step, continue to autotermination code, below
            if step_num < len(cluster._steps) - 1:
                return

if step['Status']['State'] in ('PENDING', 'RUNNING'):
                            step['Status']['State'] = 'CANCELLED'

                return

            # complete step
            step['Status']['State'] = 'COMPLETED'
            step['Status']['Timeline']['EndDateTime'] = now

            # create fake output if we're supposed to write to S3
            output_uri = self._get_step_output_uri(step['Config']['Args'])
            if output_uri and is_s3_uri(output_uri):
                mock_output = self.mock_emr_output.get(
                    (cluster_id, step_num)) or [b'']

                bucket_name, key_name = parse_s3_uri(output_uri)

                # write output to S3
                for i, part in enumerate(mock_output):
                    add_mock_s3_data(self.mock_s3_fs, {
                        bucket_name: {key_name + 'part-%05d' % i: part}})
            elif (cluster_id, step_num) in self.mock_emr_output:
                raise ValueError(
                    "can't use output for cluster ID %s, step %d "
                    "(it doesn't output to S3)" %
                    (cluster_id, step_num))

            # done!
            # if this is the last step, continue to autotermination code, below
            if step_num < len(cluster['_Steps']) - 1:
                return

self.add_mock_s3_data({'walrus': {'logs/j-MOCKCLUSTER0/1': b'1\n'}})
        stdin = BytesIO(b'foo\nbar\n')

        mr_job = MRTwoStepJob(['-r', 'emr', '-v',
                               '--s3-log-uri', 's3://walrus/logs',
                               '-', '--cleanup', mode])
        mr_job.sandbox(stdin=stdin)

        with mr_job.make_runner() as runner:
            s3_tmp_dir = runner._opts['s3_tmp_dir']
            tmp_bucket, _ = parse_s3_uri(s3_tmp_dir)

            runner.run()

            # this is set and unset before we can get at it unless we do this
            log_bucket, _ = parse_s3_uri(runner._s3_log_dir())

            list(runner.stream_output())

        conn = runner.fs.make_s3_conn()
        bucket = conn.get_bucket(tmp_bucket)
        self.assertEqual(len(list(bucket.list())), tmp_len)

        bucket = conn.get_bucket(log_bucket)
        self.assertEqual(len(list(bucket.list())), log_len)

stdin = StringIO('foo\nbar\n')

        mr_job = MRTwoStepJob(['-r', 'emr', '-v',
                               '-c', self.mrjob_conf_path,
                               '--s3-log-uri', 's3://walrus/logs',
                               '-', '--cleanup', mode])
        mr_job.sandbox(stdin=stdin)

        with mr_job.make_runner() as runner:
            s3_scratch_uri = runner._opts['s3_scratch_uri']
            scratch_bucket, _ = parse_s3_uri(s3_scratch_uri)

            runner.run()

            # this is set and unset before we can get at it unless we do this
            log_bucket, _ = parse_s3_uri(runner._s3_job_log_uri)

            list(runner.stream_output())

        conn = runner.make_s3_conn()
        bucket = conn.get_bucket(scratch_bucket)
        self.assertEqual(len(list(bucket.list())), scratch_len)

        bucket = conn.get_bucket(log_bucket)
        self.assertEqual(len(list(bucket.list())), log_len)

def _test_remote_scratch_cleanup(self, mode, scratch_len, log_len):
        self.add_mock_s3_data({'walrus': {'logs/j-MOCKJOBFLOW0/1': '1\n'}})
        # read from STDIN, a local file, and a remote file
        stdin = StringIO('foo\nbar\n')

        mr_job = MRTwoStepJob(['-r', 'emr', '-v',
                               '-c', self.mrjob_conf_path,
                               '--s3-log-uri', 's3://walrus/logs',
                               '-', '--cleanup', mode])
        mr_job.sandbox(stdin=stdin)

        with mr_job.make_runner() as runner:
            s3_scratch_uri = runner._opts['s3_scratch_uri']
            scratch_bucket, _ = parse_s3_uri(s3_scratch_uri)

            runner.run()

            # this is set and unset before we can get at it unless we do this
            log_bucket, _ = parse_s3_uri(runner._s3_job_log_uri)

            list(runner.stream_output())

        conn = runner.make_s3_conn()
        bucket = conn.get_bucket(scratch_bucket)
        self.assertEqual(len(list(bucket.list())), scratch_len)

        bucket = conn.get_bucket(log_bucket)
        self.assertEqual(len(list(bucket.list())), log_len)

def _get_s3_key(self, uri):
        """Get the boto3 s3.Object matching the given S3 uri, or
        return None if that key doesn't exist.

        uri is an S3 URI: ``s3://foo/bar``
        """
        bucket_name, key_name = parse_s3_uri(uri)
        return self.get_bucket(bucket_name).Object(key_name)