Vapor Fluent - multiple insertions in PostgreSQL from a request

NoteController.swift

final class NoteController {

    // NotesRequest is a struct that represents the request body
    // It contains a function that returns a [Note] array.
    // The line 9 creates a Note for each item in the array 
    func create(_ req: Request) throws -> Future<HTTPStatus> {
        return try req.content.decode(NotesRequest.self).flatMap { notesRequest in
            return NotesRequest.toNotes(notesRequest: notesRequest)
                .map { item in Note(id: nil,
                                        text: item.text,
                                        retroId: item.retroId!,
                                        laneId: item.laneId!)
                    .create(on: req) }
                .flatten(on: req)
                .transform(to: .ok)
            }
    }
}