class_docstr: Fetch training curve data from CloudWatch Metrics for a specific training job.
docstr: Helper method to discover the metrics defined for a training job.
docstr_tok: ["Helper","method","to","discover","the","metrics","defined","for","a","training","job","."]
code: def _metric_names_for_training_job(self):
      """Helper method to discover the metrics defined for a training job."""
      training_description = self._sage_client.describe_training_job(
          TrainingJobName=self._training_job_name
      )
  
      metric_definitions = training_description[
          "AlgorithmSpecification"
      ]["MetricDefinitions"]
      metric_names = [md["Name"] for md in metric_definitions]
  
      return metric_names
  
imports: from __future__ import print_function, absolute_import
  from abc import ABCMeta, abstractmethod
  from collections import defaultdict, OrderedDict
  import datetime
  import logging
  from six import with_metaclass
  from sagemaker.session import Session
  from sagemaker.utils import DeferredError
  from sagemaker.lineage import artifact
label_desc: Use image node_id 9 for calling the TrainingJobAnalytics obj's underlying member method code with example usage: obj._metric_names_for_training_job() and returns: metric_names