code: def _compute_artifact_size(
      artifact_file_list: List[ArtifactFileData],
  ):
      artifact_size = 0
      for artifact_file in artifact_file_list:
          if artifact_file.size is None:
              # whole artifact's size is undefined in this case
              return None
          artifact_size += artifact_file.size
      return artifact_size
  
imports: from typing import Dict, List, Optional, Tuple, Type
  from bravado.exception import HTTPNotFound
  from neptune.common.backends.utils import with_api_exceptions_handler
  from neptune.exceptions import ArtifactNotFoundException, ArtifactUploadingError, FetchAttributeNotFoundException, NeptuneEmptyLocationException
  from neptune.internal.artifacts.file_hasher import FileHasher
  from neptune.internal.artifacts.types import ArtifactDriver, ArtifactDriversMap, ArtifactFileData
  from neptune.internal.backends.api_model import ArtifactAttribute, ArtifactModel
  from neptune.internal.backends.swagger_client_wrapper import SwaggerClientWrapper
  from neptune.internal.operation import AssignArtifact, Operation
  from neptune.internal.utils.paths import path_to_str
label_desc: Use image node_id 1 for calling a global function with example usage: _compute_artifact_size(artifact_file_list) and returns: artifact_size, None