code: func (a *asc) Get() (readSeekCloser, error) {
  	if a.Fetcher != nil {
  		return a.Fetcher.Get(a.Location)
  	}
  	return NopReadSeekCloser(nil), nil
  }
docs: // Get fetches a signature file. It returns nil and no error if there
  // was no fetcher set.