text: from org.python.tests.identity import IdentityObject
  
  class PyIdentityObject (IdentityObject):
      pass
  
  x = IdentityObject()
  y = x.getThis()
          
  a = PyIdentityObject()
  b = a.getThis()
          
  assert x is y
  assert not(x is not y)
  assert (x is y)  !=  (x is not y)
  assert a is b
  assert not(a is not b)
  assert (a is b)  !=  (a is not b)
  
  