def file_record_to_url(file_records) -> list:
    """
    Translate a Json dictionary to an usable http url for downloading files.

    Parameters
    ----------
    file_records : dict
        JSON containing a 'data_url' field

    Returns
    -------
    list of str
        A list of full data urls
    """
    urls = []
    for fr in file_records:
        if fr['data_url'] is not None:
            urls.append(fr['data_url'])
    return urls