code: def three_node_clique():
      graph = nx.Graph()
      graph.add_nodes_from([1, 2, 3])
      graph.add_edges_from([(1, 2), (1, 3), (2, 3)])
      return graph
  
imports: import itertools
  import pytest
  import networkx
label_desc: Use image node_id 7 for calling a global function with example usage: three_node_clique() and returns: graph