code: def serialize(self, data):
      js = {"instances": []}
      for row in data:
          js["instances"].append({"features": row.tolist()})
      return json.dumps(js)
  
imports: from __future__ import absolute_import
  import json
  import os
  import pytest
  from sagemaker import image_uris, utils
  from sagemaker.analytics import HyperparameterTuningJobAnalytics
  from sagemaker.deserializers import JSONDeserializer
  from sagemaker.estimator import Estimator
  from sagemaker.serializers import SimpleBaseSerializer
  from sagemaker.tuner import ContinuousParameter, IntegerParameter, HyperparameterTuner
  from tests.integ import datasets, DATA_DIR, TUNING_DEFAULT_TIMEOUT_MINUTES
  from tests.integ.timeout import timeout, timeout_and_delete_endpoint_by_name
label_desc: Use image node_id 1 for calling the PredictionDataSerializer obj's underlying member method code with example usage: obj.serialize(data) and returns: json