code: def test_serialize_bytes_payload(self, mock_get_object_cached):
      mock_get_object_cached.return_value = "7897"
      payload = JumpStartSerializablePayload(
          {
              "content_type": "audio/wav",
              "body": "$s3<inference-notebook-assets/speaker_1_angry.wav>",
          }
      )
      serialized_payload = self.payload_serializer.serialize(payload)
      self.assertEqual(serialized_payload, "7897")
  
file_path: sagemaker-python-sdk/tests/unit/sagemaker/jumpstart/test_payload_utils.py
imports: from __future__ import absolute_import
  import base64
  from unittest import TestCase
  from mock.mock import patch
  from sagemaker.jumpstart.payload_utils import PayloadSerializer, _construct_payload
  from sagemaker.jumpstart.types import JumpStartSerializablePayload
  from tests.unit.sagemaker.jumpstart.utils import get_special_model_spec
label_desc: Use image node_id 1 for calling the TestPayloadSerializer obj's underlying member method code with example usage: obj.test_serialize_bytes_payload(mock_get_object_cached) without return types