Hi thanks for the useful article, just one quick question, when you tested the endpoint with command `$ aws sagemaker-runtime invoke-endpoint --endpoint-name mnist-test --body file://payload.json --content-type application/json result.json`, is this in bash? & where did you store the payload (how to specify the path `file://payload.json`)? My input files are stored in S3 bucket, not sure how to test the endpoint.

Hope this makes sense, thanks.