Deploy Websocket example resulted in error

Hi guys,
I was trying out websocket with serverless and tried to deploy the Serverless’s example code but got the following error:



TypeError: Cannot read property 'replace' of undefined
      at Object.getNormalizedWebsocketsRouteKey (C:\Users\AAA\AppData\Roaming\npm\node_modules\serverless\lib\plugins\aws\lib\naming.js:221:8)
      at Object.getWebsocketsRouteLogicalId (C:\Users\AAA\AppData\Roaming\npm\node_modules\serverless\lib\plugins\aws\lib\naming.js:229:20)
      at C:\Users\AAA\AppData\Roaming\npm\node_modules\serverless\lib\plugins\aws\package\compile\events\websockets\lib\routes.js:12:61
      at Array.forEach (<anonymous>)
      at AwsCompileWebsockets.compileRoutes (C:\Users\AAA\AppData\Roaming\npm\node_modules\serverless\lib\plugins\aws\package\compile\events\websockets\lib\routes.js:7:27)
      at AwsCompileWebsockets.tryCatcher (C:\Users\AAA\AppData\Roaming\npm\node_modules\serverless\node_modules\bluebird\js\release\util.js:16:23)
      at Promise._settlePromiseFromHandler (C:\Users\AAA\AppData\Roaming\npm\node_modules\serverless\node_modules\bluebird\js\release\promise.js:547:31)        
      at Promise._settlePromise (C:\Users\AAA\AppData\Roaming\npm\node_modules\serverless\node_modules\bluebird\js\release\promise.js:604:18)
      at Promise._settlePromise0 (C:\Users\AAA\AppData\Roaming\npm\node_modules\serverless\node_modules\bluebird\js\release\promise.js:649:10)
      at Promise._settlePromises (C:\Users\AAA\AppData\Roaming\npm\node_modules\serverless\node_modules\bluebird\js\release\promise.js:729:18)
      at _drainQueueStep (C:\Users\AAA\AppData\Roaming\npm\node_modules\serverless\node_modules\bluebird\js\release\async.js:93:12)
      at _drainQueue (C:\Users\AAA\AppData\Roaming\npm\node_modules\serverless\node_modules\bluebird\js\release\async.js:86:9)
      at Async._drainQueues (C:\Users\AAA\AppData\Roaming\npm\node_modules\serverless\node_modules\bluebird\js\release\async.js:102:5)
      at Immediate.Async.drainQueues [as _onImmediate] (C:\Users\AAA\AppData\Roaming\npm\node_modules\serverless\node_modules\bluebird\js\release\async.js:15:14)
      at processImmediate (internal/timers.js:461:21)

This a bug or I have done something wrong?

My serverless version:
Framework Core: 2.41.1
Plugin: 4.6.0
SDK: 4.2.2
Components: 3.9.2

Thank you.