just im testing the output of flow to a s3 bcuket for that i define the below things on my flow decorator @flow(name="generic model flow", persist_result=True, result_storage='s3-bucket/output-block', result_serializer="json") def churn_forecast(model_input={}): only these 3 things i defined in my flow.py persist_result=True, result_storage='s3-bucket/output-block', result_serializer="json"