def METHOD_NAME(cls, v: ImportFile, values):
    local_path = os.path.join(os.path.dirname(values["filepath"]), v.name)
    if not os.path.isfile(local_path):
        logging.error("Import file not found: %s", local_path)
        raise FileNotFoundError(local_path)
    v.content = open(local_path).read()
    return v