code: def test_bidirectional_edges():
      """A tournament must not have any pair of nodes with greater
      than one edge joining the pair.
  
      """
      G = DiGraph()
      G.add_edges_from([(0, 1), (1, 2), (2, 3), (3, 0), (1, 3), (0, 2)])
      G.add_edge(1, 0)
      assert not is_tournament(G)
  
imports: from itertools import combinations
  import pytest
  from networkx import DiGraph
  from networkx.algorithms.tournament import hamiltonian_path, index_satisfying, is_reachable, is_strongly_connected, is_tournament, random_tournament, score_sequence, tournament_matrix
label_desc: Use image node_id 6 for calling a global function with example usage: test_bidirectional_edges() without return types