code: def test_is_directed(self):
      assert self.G.is_directed() == nx.is_directed(self.G)
      assert self.DG.is_directed() == nx.is_directed(self.DG)
  
imports: import random
  import pytest
  import networkx
  from networkx.utils import edges_equal, nodes_equal
label_desc: Use image node_id 8 for calling the TestFunction obj's underlying member method code with example usage: obj.test_is_directed() without return types