def concat_to_pair_list(pair_list, prefix='', suffix=''):
    """ Add prefix and suffix to the strings in a a list of 2-tuple str.

    Parameters
    ----------
    pair_list: list of 2-tuples of str

    prefix: str

    suffix: str

    Returns
    -------
    formatted_pair_list: list of 2-tuples of str
    """
    return [(prefix + s[0] + suffix, prefix + s[1] + suffix) for s in pair_list]