code: def test_is_clique(self):
      G = UndirectedGraph(
          [
              ("A", "B"),
              ("C", "B"),
              ("B", "D"),
              ("B", "E"),
              ("D", "E"),
              ("E", "F"),
              ("D", "F"),
              ("B", "F"),
          ]
      )
      self.assertFalse(G.is_clique(nodes=["A", "B", "C", "D"]))
      self.assertTrue(G.is_clique(nodes=["B", "D", "E", "F"]))
      self.assertTrue(G.is_clique(nodes=["D", "E", "B"]))
  
imports: from pgmpy.base import UndirectedGraph
  from pgmpy.tests import help_functions
  import unittest
label_desc: Use image node_id 1 for calling the TestUndirectedGraphMethods obj's underlying member method code with example usage: obj.test_is_clique() without return types