I am trying to add Bitcoin to stripe and this what I made for BitcoinReceiver Stripe Resource.

PHP Code:
<?php

class Stripe_BitcoinReceiver extends Stripe_ApiResource
{
    
/**
     * @return string The class URL for this resource. It needs to be special
     *    cased because it doesn't fit into the standard resource pattern.
     */
    
public static function classUrl()
    {
        return 
"/v1/bitcoin/receivers";
    }

    
/**
     * @return string The instance URL for this resource. It needs to be special
     *    cased because it doesn't fit into the standard resource pattern.
     */
    
public function instanceUrl()
    {
        
$result parent::instanceUrl();
        if (
$result) {
            return 
$result;
        } else {
            
$id $this['id'];
            
$id Util\Util::utf8($id);
            
$extn urlencode($id);
            
$base BitcoinReceiver::classUrl();
            return 
"$base/$extn";
        }
    }

    
/*
     * @return BitcoinReceiver
     */
    
public static function retrieve($id$apiKey=null)
  {
    
$class get_class();
    return 
self::_scopedRetrieve($class$id$apiKey);
  }

    
/*
     * @return Collection of BitcoinReceivers
     */
    
public static function all($params=null$apiKey=null)
  {
    
$class get_class();
    return 
self::_scopedAll($class$params$apiKey);
  }


    
/*
     * @return BitcoinReceiver The created Bitcoin Receiver item.
     */
    
public static function create($params=null$apiKey=null)
  {
    
$class get_class();
    return 
self::_scopedCreate($class$params$apiKey);
  }

    
/*
     * @return BitcoinReceiver The refunded Bitcoin Receiver item.
     */
    
public function refund($params=null)
  {
    
$requestor = new Stripe_ApiRequestor($this->_apiKey);
    
$url $this->instanceUrl() . '/refund';
    list(
$response$apiKey) = $requestor->request('post'$url$params);
    
$this->refreshFrom($response$apiKey);
    return 
$this;
  }
}