def generate_new_uri(params):
    """
    Generate new magnet uri from params dictionary
    :param params: list of trackers
    :return: a string in URI / Magnet format
    """
    uri = 'magnet:?'
    uri = uri + 'xt=' + params['xt'] + '&'
    for tr in params['tr']:
        uri = uri + 'tr=' + tr + '&'
    return uri[:-1]