EasyPost\Shipment::label PHP Method

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