code: def test_topological_sort_single_node():
      graph = DiGraph()
      graph.add_node(0)
      assert graph.topological_sort() == [0]
  
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 13 for calling a global function with example usage: test_topological_sort_single_node() without return types