def s(word, seq, suffix='s'):
    """Adds a suffix to ``word`` if some sequence has anything other than
    exactly one element.

    Parameters
    ----------
    word : str
        The string to add the suffix to.
    seq : sequence
        The sequence to check the length of.
    suffix : str, optional.
        The suffix to add to ``word``

    Returns
    -------
    maybe_plural : str
        ``word`` with ``suffix`` added if ``len(seq) != 1``.
    """
    if len(seq) == 1:
        return word
    return word + suffix
