code: def test_multigraph(self):
      G = nx.MultiGraph()
      nx.add_cycle(G, [0, 1, 2, 3])
      G.add_edge(1, 2)
      G.add_edge(1, 2)
      edges = list(nx.eulerian_circuit(G, source=0))
      nodes = [u for u, v in edges]
      assert nodes == [0, 3, 2, 1, 2, 1]
      assert edges == [(0, 3), (3, 2), (2, 1), (1, 2), (2, 1), (1, 0)]
  
imports: import collections
  import pytest
  import networkx
label_desc: Use image node_id 3 for calling the TestEulerianCircuit obj's underlying member method code with example usage: obj.test_multigraph() without return types