Capacitor/CAPPluginCall.swift:52: Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value

[Baymax408]

AppDelegate.swift
typealias JSObject = [String:Any]
let call = CAPPluginCall();
var ret = JSObject()

public func AlipayCall(_ code: String) {
    switch code {
        case "9000":
        ret["message"] = ALIPAY_RESPONSE_PAY_OK;
        ret["code"] = "9000";
        call.resolve(ret);

CAPPluginCall.swift
func resolve(_ data: PluginCallResultData = [:]) {
successHandler(CAPPluginCallResult(data), self) // error line
}