public function insure($params = null)
{
$requestor = new Requestor($this->_apiKey);
$url = $this->instanceUrl() . '/insure';
if (!isset($params['amount'])) {
$clone = $params;
unset($params);
$params['amount'] = $clone;
}
list($response, $apiKey) = $requestor->request('post', $url, $params);
$this->refreshFrom($response, $apiKey);
return $this;
}