code: def test_pure_virtual(self):
      p = P()
      self.assertRaises(RuntimeError, p.f)
  
      q = Q()
      self.assertEqual("Q::f()", q.f())
  
      class R(P):
          def f(self):
              return "R.f"
  
      r = R()
      self.assertEqual("R.f", r.f())
  
file_path: turicreate/src/external/boost/boost_1_68_0/libs/python/test/polymorphism.py
imports: import unittest
  from polymorphism_ext import *
label_desc: Use image node_id 6 for calling the PolymorphTest obj's underlying member method code with example usage: obj.test_pure_virtual() and returns: str