conn.srem('key', 'item2')
conn.ismember('key', 'item') # not sure
conn.scard('key')
conn.smembers('key')
conn.smove('key1', 'key2', 'item')
conn.sdiff('key1', 'key2', 'key3') # 返回存在第一个集合，不在其他集合的元素
conn.sinter('key1', 'key2')
conn.sunion('key1', 'key2',)
# string
conn.set('key', '15')
conn.get('key')
conn.incr('key') # conn.incr('key', 1)
conn.incr('key', 5)
conn.decr('key', 5)
conn.incrbyfloat('key')
conn.incrbyfloat('key', -4.5)
conn.append('key', ' world')
conn.substr('key', 0, -2)
conn.setrange('key', 11, ' world!')
# zset
conn.zadd('zkey', 'member', 10, 'member1', 20)
conn.zrem('zkey', 'member1')
conn.zcard('zkey')
conn.zincrby('zkey', 'member', 10)
conn.zcount('zkey', 10, 20)
conn.zrank('zkey', 'member') # 分值从小到大排列
conn.zscore('zkey', 'member')
conn.zrange('zkey', 0, 9, withscores=True) # 返回前10名的成员和分数
conn.zinterstore('zset-u', ['zset1', 'zset2'], aggregate='sum') # 成员的交集，聚合函数默认为sum，成员排名相加后为新的排名
