code: def test_quotient_graph_edge_relation():
      """Tests for specifying an alternate edge relation for the quotient
      graph.
  
      """
      G = nx.path_graph(5)
  
      def identity(u, v):
          return u == v
  
      def same_parity(b, c):
          return arbitrary_element(b) % 2 == arbitrary_element(c) % 2
  
      actual = nx.quotient_graph(G, identity, same_parity)
      expected = nx.Graph()
      expected.add_edges_from([(0, 2), (0, 4), (2, 4)])
      expected.add_edge(1, 3)
      assert nx.is_isomorphic(actual, expected)
  
imports: import pytest
  import networkx
  from networkx.utils import arbitrary_element, edges_equal, nodes_equal
label_desc: Use image node_id 3 for calling a global function with example usage: test_quotient_graph_edge_relation() and returns: unknown, unknown