Return a list of normalized locales that do not throw an ``Exception``
    when set.

    Parameters
    ----------
    locales : str
        A string where each locale is separated by a newline.
    normalize : bool
        Whether to call ``locale.normalize`` on each locale.

    Returns
    -------
    valid_locales : list
        A list of valid locales.

def _valid_locales(locales, normalize):
    """
    Return a list of normalized locales that do not throw an ``Exception``
    when set.

    Parameters
    ----------
    locales : str
        A string where each locale is separated by a newline.
    normalize : bool
        Whether to call ``locale.normalize`` on each locale.

    Returns
    -------
    valid_locales : list
        A list of valid locales.
    """
    if normalize:
        normalizer = lambda x: locale.normalize(x.strip())
    else:
        normalizer = lambda x: x.strip()

    return list(filter(can_set_locale, map(normalizer, locales)))