private function connection__predis() {
		$args = [];
		foreach (array_keys($this->verified_params) as $key) {
			if ($key == 'redistype' || !$this->$key)
				continue;
			$args[substr($key, 5)] = $this->$key;
		}
		try {
			$this->connection = new \Predis\Client($args);
			$this->connection->ping();
			return $this->connection_open_ok();
		} catch(\Predis\Connection\ConnectionException $e) {
			return $this->connection_open_fail($e->getMessage());
		}
	}