code: def multigraph_test_graph():
      G = nx.MultiGraph()
      G.add_edge(1, 2, weight=7)
      G.add_edge(1, 2, weight=70)
      return G
  
imports: import pytest
  import networkx
  from networkx.generators.classic import barbell_graph, cycle_graph, path_graph
  from networkx.utils import graphs_equal
label_desc: Use image node_id 1 for calling a global function with example usage: multigraph_test_graph() and returns: G