@tornado.gen.coroutine
    def setprop(self, ctx, loctx, key, val):
        if ctx.level != LEVEL_EXECUTE:
            raise Exception('Properties may only be set in action code (location prop "%s")' % (key,))
        iid = loctx.iid
        locid = self.locid
        app = ctx.app
        
        tup = ('instanceprop', iid, locid, key)
        yield app.propcache.set(tup, val)
        ctx.task.changeset.add(tup)
INTEGRATION: update a value
dataset/ETHPy150Open erkyrath/tworld/lib/two/execute.py/LocationProxy.setprop--crossover with--dataset/ETHPy150Open jplana/python-etcd/src/etcd/tests/integration/test_simple.py/TestSimple.test_update