code: def test_eulerian_path_undirected(self):
      G = nx.Graph()
      result = [(1, 2), (2, 3), (3, 4), (4, 5)]
      result2 = [(5, 4), (4, 3), (3, 2), (2, 1)]
      G.add_edges_from(result)
      assert list(nx.eulerian_path(G)) in (result, result2)
      assert result == list(nx.eulerian_path(G, source=1))
      assert result2 == list(nx.eulerian_path(G, source=5))
      with pytest.raises(nx.NetworkXError):
          list(nx.eulerian_path(G, source=3))
      with pytest.raises(nx.NetworkXError):
          list(nx.eulerian_path(G, source=2))
  
imports: import collections
  import pytest
  import networkx
label_desc: Use image node_id 5 for calling the TestEulerianPath obj's underlying member method code with example usage: obj.test_eulerian_path_undirected() without return types