fix simple error

http = HttpHandler() do req::Request, res::Response

    parts = split(req.resource, '/', limit=3)

    procId = parts[2]

    println("$procId - ",join(parts[3:end], ', '))

    println("$procId - ", join(parts[3:end], ", "))

    if parts[3] == "preop"

        fdata = build_features(procId, "preop", preopFeatureNames, args["raw-data-dir"])

        res.data = json(explained_pred(