code: def testLength(self):
      self.assertRaises(TypeError, len, Graph(15))
      self.assertTrue(len(Graph(15).vs) == 15)
      self.assertTrue(len(Graph.Full(5).es) == 10)
  
imports: import unittest
  from igraph import Graph, disjoint_union, intersection, union
label_desc: Use image node_id 27 for calling the OperatorTests obj's underlying member method code with example usage: obj.testLength() without return types