Method contains

/**
 * Check if the cache contains data stored by ID and group
 *
 * @param   string  $id     The cache data ID
 * @param   string  $group  The cache data group
 *
 * @return  boolean
 *
 * @since   3.7.0
 */
public function contains($id, $group)
{
    if (static::isConnected() == false) {
        return false;
    }
    // Redis exists returns integer values lets convert that to boolean see: https://redis.io/commands/exists
    return (bool) static::$_redis->exists($this->_getCacheId($id, $group));
}