code: def testUnhashableVertexNames(self):
      g = Graph.Famous("bull")
      g.vs["name"] = [str(x) for x in range(4)]
  
      value = "this is not hashable".split()
      g.vs[2]["name"] = value
  
      # Trigger an indexing by doing a lookup by name
      try:
          g.vs.find("3")
          err = None
      except Exception as ex:
          err = ex
  
      # Check the exception
      self.assertTrue(isinstance(err, RuntimeError))
      self.assertTrue(repr(value) in str(err))
  
imports: import unittest
  from igraph import Graph
label_desc: Use image node_id 8 for calling the AttributeTests obj's underlying member method code with example usage: obj.testUnhashableVertexNames() without return types