code: def test_node_ordering():
      graph = DiGraph()
      nodes = [10, 0, 20, 40, 30]
      for node in nodes:
          graph.add_node(node)
  
      assert list(graph) == nodes
  
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 15 for calling a global function with example usage: test_node_ordering() without return types