Braintree\Transaction::credit PHP Method

    public static function credit($attribs)
    {
        return Configuration::gateway()->transaction()->credit($attribs);
    }

 /**
  * credit a customer for the passed transaction
  *
  * @access public
  * @param int $customerId
  * @param array $transactionAttribs
  * @return Result\Successful|Result\Error
  */
 public function credit($customerId, $transactionAttribs)
 {
     $this->_validateId($customerId);
     return Transaction::credit(array_merge($transactionAttribs, ['customerId' => $customerId]));
 }