code: def testEmpty(self):
      g = Graph()
      t = g.gomory_hu_tree()
      self.assertEqual(0, t.vcount())
      self.assertEqual(0, t.ecount())
  
imports: import unittest
  from igraph import Cut, Graph, EdgeSeq, InternalError
  from itertools import combinations
  from random import randint
label_desc: Use image node_id 1 for calling the GomoryHuTests obj's underlying member method code with example usage: obj.testEmpty() without return types