code: def valid_buckets():
      return [
          "this_bucket_is_valid",
          "th15_8uck3t_15_v4l1d",
          "this-bucket-is-valid",
          "this-bucket.is-valid",
      ]
  
imports: import pytest
  import datetime
  import os
  import json
  from sacred.observers import GoogleCloudStorageObserver
label_desc: Use image node_id 18 for calling a global function with example usage: valid_buckets() and returns: list