I am migrating my lambda applications from serverless framework to CDK. I am fairly new to CDK and wondering if I am missing something here. I have my lambda code in ./lambda/hello.js. I am trying to deploy this to lambda. In my previous successful deployments I have directly used Code.fromAsset which was uploading the zip file to a random S3 bucket created by CDK. I am now trying to upload this to a custom bucket which already exists. In serverless, I used to just mention this bucket name and my zip files used to get upload there and lambda deployment happened from that file.