code: def test_mutag_load() -> None:
      _graph_kernels_load(
          MUTAG(),
          n_graphs=188,
          total_nodes=3371,
          max_nodes=28,  # graph 6
          total_edges=7442,
          expected_labels={"-1", "1"},
          node_features=7,  # 7 labels
          mean_nodes=17.93,
          mean_edges=19.79,
      )
  
imports: import pytest
  import tempfile
  import os
  import sys
  import numpy
  from stellargraph.datasets import *
  from urllib.error import URLError
  from stellargraph.datasets.dataset_loader import DatasetLoader
  from urllib.request import urlretrieve
  from unittest.mock import patch
label_desc: Use image node_id 8 for calling a global function with example usage: test_mutag_load() without return types