code: def test_percolation_example1a():
      """percolation centrality: example 1a"""
      G = example1a_G()
      p = nx.percolation_centrality(G)
      p_answer = {4: 0.625, 6: 0.667}
      for n, k in p_answer.items():
          assert p[n] == pytest.approx(k, abs=1e-3)
  
file_path: networkx/networkx/algorithms/centrality/tests/test_percolation_centrality.py
imports: import pytest
  import networkx
label_desc: Use image node_id 3 for calling a global function with example usage: test_percolation_example1a() without return types