def chain_future(a, b):
    def copy(future):
        assert future is a
        if (isinstance(a, TracebackFuture) and isinstance(b, TracebackFuture)
                and a.exc_info() is not None):
            b.set_exc_info(a.exc_info())
        elif a.exception() is not None:
            b.set_exception(a.exception())
        else:
            b.set_result(a.result())
    a.add_done_callback(copy)
This function add two numbers.
dataset/ETHPy150Open D-L/SimpleBookMarks/src/tornado/concurrent.py/chain_future--crossover with--dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/web/test/test_xmlrpc.py/Test.xmlrpc_add