code: def testVertexConnectivity(self):
      self.assertTrue(self.g.vertex_connectivity(0, 3) == 2)
      self.assertTrue(Graph.Barabasi(50).vertex_connectivity() == 1)
      self.assertTrue(self.g.cohesion() == 2)
      self.assertTrue(Graph.Tree(10, 3).cohesion() == 1)
      self.assertTrue(Graph.Tree(10, 3, "out").cohesion() == 0)
      self.assertRaises(ValueError, self.g.vertex_connectivity, 0)
      self.assertRaises(InternalError, self.g.vertex_connectivity, 0, 1)
      self.assertTrue(
          self.g.vertex_connectivity(0, 1, neighbors="nodes") == 4
      )
      self.assertTrue(
          self.g.vertex_connectivity(0, 1, neighbors="negative") == -1
      )
  
imports: import unittest
  from igraph import Cut, Graph, EdgeSeq, InternalError
  from itertools import combinations
  from random import randint
label_desc: Use image node_id 4 for calling the MaxFlowTests obj's underlying member method code with example usage: obj.testVertexConnectivity() without return types