def __set__(self, model_instance, value):
    raise BadValueError('Virtual property is read-only')
>>> text = '''
dataset/ETHPy150Open CollabQ/CollabQ/.google_appengine/google/appengine/ext/db/__init__.py/_ReverseReferenceProperty.__set__--crossover with--dataset/ETHPy150Open limodou/par/test/test_md.py/test_pre_1