def METHOD_NAME(res, delimiter, fname=None):
    """Get an iterator over the CSV data from the response."""
    if res.status_code == 200:
        # Python 2 -- csv.reader will need bytes
        if sys.version_info[0] < 3:
            csv_io = BytesIO(res.content)
            # Optionally write to file
            if fname:
                with open(fname, 'wb') as fh:
                    fh.write(res.content)
        # Python 3 -- csv.reader needs str
        else:
            csv_io = StringIO(res.text)
            # Optionally write to file
            if fname:
                with open(fname, 'wt') as fh:
                    fh.write(res.text)
        data_iter = read_unicode_csv_fileobj(csv_io, delimiter=delimiter,
                                             skiprows=1)
    else:
        raise Exception('Could not download Signor data.')
    return data_iter