nominal retryable = ()
nominal non_retryable = ()

union request effect result =
    | QueryStatus :: string -> request retryable string
    | SubmitNfe :: string -> request non_retryable string

inl run_request forall effect result.
    (request : request effect result)
    : result =
    match request with
    | QueryStatus protocol => protocol
    | SubmitNfe payload => payload

inl retry forall result.
    (request : request retryable result)
    : result =
    run_request request

inl main () : string =
    retry (SubmitNfe "duplicate-risk")