class_docstr: ArtifactExtractor class will extract artifacts from "streamalert_normalization" field in the
  records. The extracted artfiacts will be saved in the S3 bucket via a dedicated Firehose
  delivery stream and searchable from "artifacts" table in Athena.
code: def firehose(self):
      return ArtifactExtractor._firehose_client
  
file_path: streamalert/streamalert/shared/artifact_extractor.py
imports: import re
  import uuid
  from streamalert.shared.firehose import FirehoseClient
  from streamalert.shared import CLASSIFIER_FUNCTION_NAME, config
  from streamalert.shared.metrics import MetricLogger
  from streamalert.shared.normalize import Normalizer, CONST_ARTIFACTS_FLAG
  from streamalert.shared.logger import get_logger
label_desc: Use image node_id 3 for calling the ArtifactExtractor obj's underlying member method code with example usage: obj.firehose() and returns: ArtifactExtractor