This update removes the dependency on the python requests library from the replace-route function and replaces it with the native urllib. alterNAT can now be deployed using AWS Lambda Python runtime which by default has all the required third-party dependencies preinstalled (boto3).
The alternat_image_* inputs are now optional. Nothing has changed for the Docker image runtime which remains the default deployment scenario.
Many thanks to @jgr-trackunit and @oponomarov-tu for this contribution!