Given that we don't have a dockerfile, my best guess is that you followed the instructions (https://docs.datadoghq.com/serverless/aws_lambda/installation/python/?tab=containerimage) and then didn't correctly set the DD_LAMBDA_HANDLER environment variable that tells Datadog where to redirect the request. If you don't, it won't be able to find your function an you'll get an import error just like the one you desribed.

Please add a dockerfile next time! It'll be much easier to help you get a solution.