code: def test_reciprocity_graph_node(self):
      DG = nx.DiGraph([(1, 2), (2, 3), (3, 2)])
      reciprocity = nx.reciprocity(DG, 2)
      assert reciprocity == 0.6666666666666666
  
file_path: networkx/networkx/algorithms/tests/test_reciprocity.py
imports: import pytest
  import networkx
label_desc: Use image node_id 4 for calling the TestReciprocity obj's underlying member method code with example usage: obj.test_reciprocity_graph_node() without return types