code: def test_can_add_same_node():
      graph = DiGraph()
      graph.add_node("A")
      graph.add_node("A")
  
file_path: baikal/tests/_core/test_digraph.py
imports: import pytest
  from baikal._core.digraph import DiGraph, NodeNotFoundError, CyclicDiGraphError
label_desc: Use image node_id 5 for calling a global function with example usage: test_can_add_same_node() without return types