iOS에서 PaymentWidget이 카드사 선택 UI를 렌더링하지 못합니다.

Error evaluating injectedJavaScript: This is possibly due to an unsupported return type. Try adding true to the end of your injectedJavaScript string. Error Domain=WKErrorDomain Code=4 "JavaScript 예외가 발생했습니다" UserInfo={WKJavaScriptExceptionLineNumber=3, WKJavaScriptExceptionMessage=ReferenceError: Can't find variable: PaymentWidget, WKJavaScriptExceptionColumnNumber=33, WKJavaScriptExceptionSourceURL=about:blank, NSLocalizedDescription=JavaScript 예외가 발생했습니다}