code: def test_generator_init_nx_graph():
      graphs_nx = [
          example_graph_random(
              feature_size=4, n_nodes=3, is_directed=False
          ),
          example_graph_random(
              feature_size=4, n_nodes=2, is_directed=False
          ).to_networkx(),
      ]
  
      with pytest.raises(
          TypeError,
          match="graphs: expected.*StellarGraph.*found MultiGraph.",
      ):
          generator = PaddedGraphGenerator(graphs=graphs_nx)
  
imports: from stellargraph.core.graph import *
  from stellargraph.mapper.padded_graph_generator import PaddedGraphGenerator, PaddedGraphSequence
  import numpy
  import pytest
  from ..test_utils.graphs import example_graph_random, example_graph, example_hin_1
label_desc: Use image node_id 4 for calling a global function with example usage: test_generator_init_nx_graph() without return types