code: def get_bucket_files(
      glob_pattern, base_dir, force=False, pattern_slice=None
  ):
      """Download files from Google Cloud Storage.
  
      Args:
          glob_pattern (str or list): Glob pattern string or series of patterns
              used to search for on Google Cloud Storage. The pattern should
              include the "gs://" protocol prefix. If a list of lists, then the
              results of each sublist pattern are concatenated and the result is
              treated as one pattern result. This is important for things like
              ``pattern_slice`` and complicated glob patterns not supported by
              GCP.
          base_dir (str): Root directory to place downloaded files on the local
              system.
          force (bool): Force re-download of data regardless of its existence on
              the local system. Warning: May delete non-demo files stored in
              download directory.
          pattern_slice (slice): Slice object to limit the number of files
              returned by each glob pattern.
  
      """
      if pattern_slice is None:
          pattern_slice = slice(None)
      if gcsfs is None:
          raise RuntimeError(
              "Missing 'gcsfs' dependency for GCS download."
          )
      if not os.path.isdir(base_dir):
          # it is the caller's responsibility to make this
          raise OSError("Directory does not exist: {}".format(base_dir))
  
      if isinstance(glob_pattern, str):
          glob_pattern = [glob_pattern]
  
      fs = gcsfs.GCSFileSystem(token="anon")  # nosec
      filenames = []
      for gp in glob_pattern:
          # handle multiple glob patterns being treated as one pattern
          # for complicated patterns that GCP can't handle
          if isinstance(gp, str):
              glob_results = list(fs.glob(gp))
          else:
              # flat list of results
              glob_results = [fn for pat in gp for fn in fs.glob(pat)]
          filenames.extend(
              _download_gcs_files(
                  glob_results[pattern_slice], fs, base_dir, force
              )
          )
  
      if not filenames:
          raise OSError("No files could be found or downloaded.")
      return filenames
  
imports: import logging
  import os
  from urllib.error import URLError
  from urllib.request import urlopen
label_desc: Use image node_id 2 for calling a global function with example usage: get_bucket_files(glob_pattern, base_dir, force, pattern_slice) and returns: filenames