code: def test_limited_bfs_layers(self):
      assert dict(enumerate(nx.bfs_layers(self.G, sources=[0]))) == {
          0: [0],
          1: [1],
          2: [2],
          3: [3, 7],
          4: [4, 8],
          5: [5, 9],
          6: [6, 10],
      }
      assert dict(enumerate(nx.bfs_layers(self.D, sources=2))) == {
          0: [2],
          1: [3, 7],
          2: [8],
          3: [9],
          4: [10],
      }
  
imports: from functools import partial
  import pytest
  import networkx
label_desc: Use image node_id 6 for calling the TestBreadthLimitedSearch obj's underlying member method code with example usage: obj.test_limited_bfs_layers() without return types