code: def test_find_negative_cycle_single_edge(self):
      G = nx.Graph()
      G.add_edge(0, 1, weight=-1)
      assert nx.find_negative_cycle(G, 1) == [1, 0, 1]
  
imports: import pytest
  import networkx
  from networkx.utils import pairwise
label_desc: Use image node_id 10 for calling the TestBellmanFordAndGoldbergRadzik obj's underlying member method code with example usage: obj.test_find_negative_cycle_single_edge() without return types