code: public function getCredits ()
  	{
  		$this->isValidData ();
  
  		$data = array ();
  
  		if (isset ($this->email))
  		{
  			$data['email'] = $this->email;
  		}
  
  		if (count($this->openid_hashed) > 0)
  		{
  			$data['openidhash'] = $this->openid_hashed[0];
  			$data['openid'] = $this->openids[0];
  		}
  
  		$data = array_merge
  		(
  			$this->data,
  			$data
  		);
  
  		$url = $this->getSignedURL (self::PAYMENT_GATEWAY_URL.'getcredits/', $data);
  
  		$data = $this->file_get_contents ($url);
  		if ($data !== false)
  		{
  			return $data;
  		}
  		else
  		{
  			return -1;
  		}
  
  		return false;
  	}
docs: /*
  Return the amount of credits this user has.