def raiser(eclass):
    raise eclass()

# test decorator for skipping tests when libraries are unavailable
1. map only subclass of class
dataset/ETHPy150Open ipython/ipython-py3k/IPython/parallel/tests/clienttest.py/raiser--crossover with--dataset/ETHPy150Open zzzeek/sqlalchemy/test/orm/test_events.py/DeferredMapperEventsTest.test_deferred_instance_event_subclass_post_mapping_propagate