Исправляемая фатальная ошибка: объект класса Instamojo не может быть преобразован в строку

Я просто работаю над проектом, который использует instamojo для оплаты. У меня есть два файла один файл instamojo.php другой файл call.php, когда я вызываю конструктор instamojo в call.php, тогда я получаю код ошибки.

*<?php
class Instamojo {
const version = '1.1';
protected $curl;
protected $endpoint = 'https://www.instamojo.com/api/1.1/';
protected $api_key = null;
protected $auth_token = null;
/**
* @param string $api_key
* @param string $auth_token is available on the d
* @param string $endpoint can be set if you are working on an alternative server.
* @return array AuthToken object.
*/
function __construct($api_key, $auth_token=null, $endpoint=null)
{
$this->api_key = (string) $api_key;
$this->auth_token = (string) $auth_token;
if(!is_null($endpoint)){
$this->endpoint = (string) $endpoint;
}
}
public function __destruct()
{
if(!is_null($this->curl)) {
curl_close($this->curl);
}
}
/**
* @return array headers with Authentication tokens added
*/
private function build_curl_headers()
{
$headers = array("X-Api-key: $this->api_key");
if($this->auth_token) {
$headers[] = "X-Auth-Token: $this->auth_token";
}
return $headers;
}
/**
* @param string $path
* @return string adds the path to endpoint with.
*/
private function build_api_call_url($path)
{
if (strpos($path, '/?') === false and strpos($path, '?') === false) {
return $this->endpoint . $path . '/';
}
return $this->endpoint . $path;
}
/**
* @param string $method ('GET', 'POST', 'DELETE', 'PATCH')
* @param string $path whichever API path you want to target.
* @param array $data contains the POST data to be sent to the API.
* @return array decoded json returned by API.
*/
private function api_call($method, $path, array $data=null)
{
$path = (string) $path;
$method = (string) $method;
$data = (array) $data;
$headers = $this->build_curl_headers();
$request_url = $this-> build_api_call_url($path);
$options = array();
$options[CURLOPT_HTTPHEADER] = $headers;
$options[CURLOPT_RETURNTRANSFER] = true;

if($method == 'POST') {
$options[CURLOPT_POST] = 1;
$options[CURLOPT_POSTFIELDS] = http_build_query($data);
} else if($method == 'DELETE') {
$options[CURLOPT_CUSTOMREQUEST] = 'DELETE';
} else if($method == 'PATCH') {
$options[CURLOPT_POST] = 1;
$options[CURLOPT_POSTFIELDS] = http_build_query($data);
$options[CURLOPT_CUSTOMREQUEST] = 'PATCH';
} else if ($method == 'GET' or $method == 'HEAD') {
if (!empty($data)) {
/* Update URL to container Query String of Paramaters */
$request_url .= '?' . http_build_query($data);
}
}
// $options[CURLOPT_VERBOSE] = true;
$options[CURLOPT_URL] = $request_url;
$options[CURLOPT_SSL_VERIFYPEER] = true;
$options[CURLOPT_CAINFO] = dirname(__FILE__) . DIRECTORY_SEPARATOR . 'cacert.pem';
$this->curl = curl_init();
$setopt = curl_setopt_array($this->curl, $options);
$response = curl_exec($this->curl);
$headers = curl_getinfo($this->curl);
$error_number = curl_errno($this->curl);
$error_message = curl_error($this->curl);
$response_obj = json_decode($response, true);
if($error_number != 0){
if($error_number == 60){
throw new \Exception("Something went wrong. cURL raised an error with number: $error_number and message: $error_message. " .
"Please check http://stackoverflow.com/a/21114601/846892 for a fix." . PHP_EOL);
}
else{
throw new \Exception("Something went wrong. cURL raised an error with number: $error_number and message: $error_message." . PHP_EOL);
}
}
if($response_obj['success'] == false) {
$message = json_encode($response_obj['message']);
throw new \Exception($message . PHP_EOL);
}
return $response_obj;
}
/**
* @return string URL to upload file or cover image asynchronously
*/
public function getUploadUrl()
{
$result = $this->api_call('GET', 'links/get_file_upload_url', array());
return $result['upload_url'];
}
/**
* @param string $file_path
* @return string JSON returned when the file upload is complete.
*/
public function uploadFile($file_path)
{
$upload_url = $this->getUploadUrl();
$file_path = realpath($file_path);
$file_name = basename($file_path);
$ch = curl_init();
$data = array('fileUpload' => $this->getCurlValue($file_path, $file_name));
curl_setopt($ch, CURLOPT_URL, $upload_url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
return curl_exec($ch);
}
public function getCurlValue($file_path, $file_name, $content_type='')
{
// http://stackoverflow.com/a/21048702/846892
// PHP 5.5 introduced a CurlFile object that deprecates the old @filename syntax
// See: https://wiki.php.net/rfc/curl-file-upload
if (function_exists('curl_file_create')) {
return curl_file_create($file_path, $content_type, $file_name);
}
// Use the old style if using an older version of PHP
$value = "@{$file_path};filename=$file_name";
if ($content_type) {
$value .= ';type=' . $content_type;
}
return $value;
}
/**
* Uploads any file or cover image mentioned in $link and
* updates it with the json required by the API.
* @param array $link
* @return array $link updated with uploaded file information if applicable.
*/
public function uploadMagic(array $link)
{
if(!empty($link['file_upload'])) {
$file_upload_json = $this->uploadFile($link['file_upload']);
$link['file_upload_json'] = $file_upload_json;
unset($link['file_upload']);
}
if(!empty($link['cover_image'])) {
$cover_image_json = $this->uploadFile($link['cover_image']);
$link['cover_image_json'] = $cover_image_json;
unset($link['cover_image']);
}
return $link;
}
/**
* Authenticate using username and password of a user.
* Automatically updates the auth_token value.
* @param array $args contains username=>USERNAME and password=PASSWORD
* @return array AuthToken object.
*/
public function auth(array $args)
{
$response = $this->api_call('POST', 'auth', $args);
$this->auth_token = $response['auth_token']['auth_token'];
return $this->auth_token;
}
/**
* @return array list of Link objects.
*/
public function linksList()
{
$response = $this->api_call('GET', 'links', array());
return $response['links'];
}
/**
* @return array single Link object.
*/
public function linkDetail($slug)
{
$response = $this->api_call('GET', 'links/' . $slug, array());
return $response['link'];
}
/**
* @return array single Link object.
*/
public function linkCreate(array $link)
{
if(empty($link['currency'])){
$link['currency'] = 'INR';
}
$link = $this->uploadMagic($link);
$response = $this->api_call('POST', 'links', $link);
return $response['link'];
}
/**
* @return array single Link object.
*/
public function linkEdit($slug, array $link)
{
$link = $this->uploadMagic($link);
$response = $this->api_call('PATCH', 'links/' . $slug, $link);
return $response['link'];
}
/**
* @return array single Link object.
*/
public function linkDelete($slug)
{
$response = $this->api_call('DELETE', 'links/' . $slug, array());
return $response;
}
/**
* @return array list of Payment objects.
*/
public function paymentsList($limit = null, $page = null)
{
$params = array();
if (!is_null($limit)) {
$params['limit'] = $limit;
}
if (!is_null($page)) {
$params['page'] = $page;
}
$response = $this->api_call('GET', 'payments', $params);
return $response['payments'];
}
/**
* @param string payment_id as provided by paymentsList() or Instamojo's webhook or redirect functions.
* @return array single Payment object.
*/
public function paymentDetail($payment_id)
{
$response = $this->api_call('GET', 'payments/' . $payment_id, array());
return $response['payment'];
}
/////   Request a Payment  /////
/**
* @param array single PaymentRequest object.
* @return array single PaymentRequest object.
*/
public function paymentRequestCreate(array $payment_request)
{
$response = $this->api_call('POST', 'payment-requests', $payment_request);
return $response['payment_request'];
}
/**
* @param string id as provided by paymentRequestCreate, paymentRequestsList, webhook or redirect.
* @return array single PaymentRequest object.
*/
public function paymentRequestStatus($id)
{
$response = $this->api_call('GET', 'payment-requests/' . $id, array());
return $response['payment_request'];
}
/**
* @param string id as provided by paymentRequestCreate, paymentRequestsList, webhook or redirect.
* @param string payment_id as received with the redirection URL or webhook.
* @return array single PaymentRequest object.
*/
public function paymentRequestPaymentStatus($id, $payment_id)
{
$response = $this->api_call('GET', 'payment-requests/' . $id . '/' . $payment_id, array());
return $response['payment_request'];
}
/**
* @param array datetime_limits containing datetime data with keys 'max_created_at', 'min_created_at',
* 'min_modified_at' and 'max_modified_at' in ISO 8601 format(optional).
* @return array containing list of PaymentRequest objects.
* For more information on the allowed date formats check the
* docs: https://www.instamojo.com/developers/request-a-payment-api/#toc-filtering-payment-requests
*/
public function paymentRequestsList($datetime_limits=null)
{
$endpoint = 'payment-requests';
if(!empty($datetime_limits)){
$query_string = http_build_query($datetime_limits);
if(!empty($query_string)){
$endpoint .= '/?' . $query_string;
}
}
$response = $this->api_call('GET', $endpoint, array());
return $response['payment_requests'];
}
/////   Refunds  /////
/**
* @param array single Refund object.
* @return array single Refund object.
*/
public function refundCreate(array $refund)
{
$response = $this->api_call('POST', 'refunds', $refund);
return $response['refund'];
}
/**
* @param string id as provided by refundCreate or refundsList.
* @return array single Refund object.
*/
public function refundDetail($id)
{
$response = $this->api_call('GET', 'refunds/' . $id, array());
return $response['refund'];
}
/**
* @return array containing list of Refund objects.
*/
public function refundsList()
{
$response = $this->api_call('GET', 'refunds', array());
return $response['refunds'];
}
}
?>*

И это instamojo.php call.php

<?php
require_once('Instamojo.php');function get_value()
{
$apii = new Instamojo("ba93dee8f492c9e6e98284decce6c5b4","838c8bc1cbd71c30e5c98bebb9e99968");
echo $apii;
/*try {
$response = $apii->paymentRequestCreate(array(
"purpose" => "FIFA 16",
"amount" => "3499",
"send_email" => true,
"email" => "[email protected]",
"redirect_url" => "http://www.example.com/handle_redirect.php"));
print_r($response);
}
catch (Exception $e) {
print('Error: ' . $e->getMessage());
}-->*/

}

if(function_exists($_GET['f'])) {
$_GET['f']();
}
?>

Но когда я вызываю call.php в браузер, я получаю сообщение об ошибке

Catchable fatal error: Object of class Instamojo could not be converted to string