def _dict_mixed_conll_formatter(v, v_delimiter):
    """
    Format a mixed value into a string representation.

    Args:
        v: The value to convert to a mixed CoNLL string format.
        v_delimiter: The delimiter between values in the string.

    Returns:
        A CoNLL representation of the mixed value.
    """
    if v is None:
        return v
    sorted_vs = sorted(v, key=str.lower)
    str_vs = v_delimiter.join(sorted_vs)
    return str_vs
