public function setCurrentGroup(string $group): Generator
    {
        $response = yield from $this->sendCommand(new Command('GROUP', $group));

        if (preg_match('/(\d+)\s+(\d+)\s+(\d+)\s+([A-z\._-]+)/', $response->message(), $matches) === false) {
            throw new FormatException('Invalid group format');
        }

        $this->group = new Group($matches[4], (int)$matches[1], (int)$matches[2], (int)$matches[3]);
        return $this->group;
    }