#assignment >> Getter, #assignment? >> Returns true if assignment is having value other than nil else false, #assignment = >> Setter. Acceptable inputs are file upload(ActionDispatch::Http::UploadedFile), filer handle and String(format validation is ignored), #assignment_path >> File path of assignment, #assignment_path_to_write >> File path of assignment to write (specific to writing. Used internally), #assignment_persisted? >> true if provided file/data is stored on disk, #assignment_store! >> to store provided file/data on disk, #assignment_destroy! >> to store destroy stored file/data from disk