code: def test_digraph():
      G = nx.DiGraph()
      nx.add_path(G, [1, 2, 3])
      H = cytoscape_graph(cytoscape_data(G))
      assert H.is_directed()
      assert nx.is_isomorphic(G, H)
  
file_path: networkx/networkx/readwrite/json_graph/tests/test_cytoscape.py
imports: import copy
  import json
  import pytest
  import networkx
  from networkx.readwrite.json_graph import cytoscape_data, cytoscape_graph
label_desc: Use image node_id 4 for calling a global function with example usage: test_digraph() without return types