Returns the string representation of the type of the value stored at key.
The different types that can be returned are: string, list, set, zset
and hash.
*Return value
Simple string reply: type of key, or none when key does not exist.
*Examples
redis>
SET key1 "value"
OKredis> LPUSH key2 "value"
(integer) 1redis> SADD key3 "value"
(integer) 1redis> TYPE key1
stringredis> TYPE key2
listredis> TYPE key3
set