code: def test_add_nodes_from_non_string(self):
      self.graph.add_nodes_from([1, 2, 3, 4])
  
imports: from pgmpy.base import UndirectedGraph
  from pgmpy.tests import help_functions
  import unittest
label_desc: Use image node_id 9 for calling the TestUndirectedGraphCreation obj's underlying member method code with example usage: obj.test_add_nodes_from_non_string() without return types