code: def test_from_networkx_graph_only():
      raw_edges = [(0, 1), (0, 2), (0, 2), (1, 2), (1, 2)]
      expected_nodes = {
          "a": pd.DataFrame(columns=range(0), index=[0, 1, 2])
      }
      expected_edges = {
          "x": pd.DataFrame(
              raw_edges, columns=["source", "target"]
          ).assign(w=W)
      }
  
      g = nx.MultiDiGraph()
      g.add_edges_from(raw_edges)
  
      nodes, edges = from_networkx_for_testing(g)
      assert_dataframe_dict_equal(nodes, expected_nodes)
      assert_dataframe_dict_equal(edges, expected_edges)
  
imports: import networkx
  import numpy
  import pandas
  import pytest
  from stellargraph.core.convert import ColumnarConverter, convert_nodes, convert_edges, from_networkx
  from stellargraph.core.indexed_array import IndexedArray
label_desc: Use image node_id 20 for calling a global function with example usage: test_from_networkx_graph_only() without return types