code: def test_from_networkx_empty():
      nodes, edges = from_networkx_for_testing(nx.DiGraph())
      assert nodes == {}
      assert 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 18 for calling a global function with example usage: test_from_networkx_empty() without return types