code: def _get_file_data(bucket, directory, filename):
      file_blob = _get_blob(bucket, directory, filename)
      return file_blob.download_as_string()
  
imports: import pytest
  import datetime
  import os
  import json
  from sacred.observers import GoogleCloudStorageObserver
label_desc: Use image node_id 8 for calling a global function with example usage: _get_file_data(bucket, directory, filename) and returns: file_blob