code: def setUp(self):
      self.graph = FactorGraph()
  
imports: import numpy
  import unittest
  from pgmpy.factors.discrete import DiscreteFactor
  from pgmpy.models import FactorGraph
  from pgmpy.models import MarkovNetwork
  from pgmpy.models import JunctionTree
  from pgmpy.tests import help_functions
label_desc: Use image node_id 1 for calling the TestFactorGraphFactorOperations obj's underlying member method code with example usage: obj.setUp() without return types