redis.set("key1", "Hello")
redis.set("key2", "World")

# Rename failed because "key2" already exists.
assert redis.renamenx("key1", "key2") == False

assert redis.renamenx("key1", "key3") == True

assert redis.get("key1") is None
assert redis.get("key2") == "World"
assert redis.get("key3") == "Hello"