code: def test_single_node_graph(self):
      G = nx.DiGraph()
      G.add_node(0)
      assert nx.is_semiconnected(G)
  
file_path: networkx/networkx/algorithms/components/tests/test_semiconnected.py
imports: from itertools import chain
  import pytest
  import networkx
label_desc: Use image node_id 3 for calling the TestIsSemiconnected obj's underlying member method code with example usage: obj.test_single_node_graph() without return types