code: def pick_add_edge(g):
      u = nx.utils.arbitrary_element(g)
      possible_nodes = set(g.nodes())
      neighbors = list(g.neighbors(u)) + [u]
      possible_nodes.difference_update(neighbors)
      v = nx.utils.arbitrary_element(possible_nodes)
      return (u, v)
  
file_path: networkx/networkx/algorithms/centrality/tests/test_closeness_centrality.py
imports: import pytest
  import networkx
label_desc: Use image node_id 10 for calling the TestClosenessCentrality obj's underlying member method code with example usage: obj.pick_add_edge(g) and returns: u,  v