A frustrating issue with ex_aws get_bucket_lifecycle

Having a frustrating issue with S3 API. Pretty much all functional calls I tried so far always return json response, which get happily translated into elixir maps and lists by Jason (thanks to

config :ex_aws, json_codec: Jason

option).
But one particular API, get_bucket_lifecycle(), returns XML. Jason then messes up the data because it thinks it’s json.
I tried adding

request = request |> struct(%{headers: Map.merge(request.headers, %{“Accept” => “application/json”})})

to force json but it had no effect.
I also tried aws s3api get-bucket-lifecycle-configuration --bucket cogynt-data --debug to see what amazon’s own tool is doing, and I’m seeing in debug output that the raw response from server is actually XML, and then they use Python’s boto to read XML into structs which then get output as json to the client.
I know there must be a reason ex_aws has a dependency on :sweet_xml library, but I’m also concerned that it’s using the outdated API, get_bucket_lifecycle instead of get-bucket-lifecycle-configuration and than I’m seemingly unable to get an elixir map/list on the output.
Any tips are much appreciated.