def add_node(node, val):
unicorn = Service('unicorn')
ch = yield unicorn.get(node)
_, version = yield ch.rx.get()
if version == -1:
ch = yield unicorn.create(node, val)
yield ch.rx.get()
else:
print 'puting data {}'.format(val)
ch = yield unicorn.put(node, val, version)
yield ch.rx.get()
