public function createSSHKey($serverId, array $data, $wait = true)
    {
        $key = $this->post("servers/$serverId/keys", $data)['key'];

        if ($wait) {
            return $this->retry($this->getTimeout(), function () use ($serverId, $key) {
                $key = $this->SSHKey($serverId, $key['id']);

                return $key->status == 'installed' ? $key : null;
            });
        }

        return new SSHKey($key + ['server_id' => $serverId], $this);
    }