code: def test_get_moral_graph():
      graph = nx.DiGraph()
      graph.add_nodes_from([1, 2, 3, 4, 5, 6, 7])
      graph.add_edges_from(
          [(1, 2), (3, 2), (4, 1), (4, 5), (6, 5), (7, 5)]
      )
      H = moral_graph(graph)
      assert not H.is_directed()
      assert H.has_edge(1, 3)
      assert H.has_edge(4, 6)
      assert H.has_edge(6, 7)
      assert H.has_edge(4, 7)
      assert not H.has_edge(1, 5)
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_get_moral_graph() without return types