The For and LimitedParallel extension states require data manipulation between states, and this is supported by a series of Lambda functions.
The Lambda function themselves can be found in the github repo, and they have been incorporated into an AWS CloudFormation script so that they can be easily added to the AWS account / region that the AWS Step Function state machines will be executed.
Once created, the Arns of the Lambda functions must be passed to the awssl package; this is the purpose of these functions.
.. automodule:: awssl.ext
.. autofunction:: get_ext_arn
.. autofunction:: get_ext_arn_keys
.. autofunction:: set_ext_arns