def rename_label(labels, old, new):
    """Rename a label in a parcellation

    Parameters
    ----------
    labels : list of Label
        The labels
    old, new : str
        Old and new names without hemi affix.

    Notes
    -----
    Modifies ``labels`` in-place, returns None.
    """
    delim = '-'
    for hemi in ('lh', 'rh'):
        old_ = delim.join((old, hemi))
        for label in labels:
            if label.name == old_:
                new_ = delim.join((new, hemi))
                label.name = new_
