code: def test_export_format_before_scaffold_assets(self):
      with self.assertRaises(ValueError):
          core.ModelCardToolkit().export_format()
  
file_path: model-card-toolkit/model_card_toolkit/core_test.py
imports: import os
  from absl import flags
  from absl.testing import absltest
  from model_card_toolkit import core
  from model_card_toolkit.proto import model_card_pb2
  from model_card_toolkit.utils import io_utils
label_desc: Use image node_id 8 for calling the CoreTest obj's underlying member method code with example usage: obj.test_export_format_before_scaffold_assets() without return types