def s3_file_obj
    s3_key = task_dataset_file.dataset_file_s3_key
    return nil if s3_key.nil?
    s3_file_obj = Aws::S3::Object.new(bucket_name: ENV['AWS_S3_BUCKET'], key: s3_key)
    if s3_file_obj && s3_file_obj.key && !s3_file_obj.key.blank?