pipe = r.pipeline()

for availability in availabilities:
    pipe.hget(availability["EventId"], "new_code")

for availability, old_code in zip(availabilities, pipe.execute()):
    if old_code:
        availability["old_code"] = old_code.decode("utf-8")

for availability in availabilities:
    if "old_code" in availability:
        pipe.hset(
            availability["EventId"], "old_code", availability["old_code"])
    pipe.hset(availability["EventId"], "new_code", availability["MsgCode"])
pipe.execute()

d = []
pipe = r.pipeline()
keys = r.keys('*')
for key in keys:
    pipe.hgetall(key)
for val, key in zip(pipe.execute(), keys):
    e = {"event_id": key}
    e.update(val)
    if "old_key" not in e:
        e["old_key"] = None
    d.append(e)