indices.

    Parameters
    ----------
    areas : str
        A string containing a sequence of column ranges (or areas).

    Returns
    -------
    cols : list
        A list of 0-based column indices.

    Examples
    --------
    >>> _range2cols('A:E')
    [0, 1, 2, 3, 4]
    >>> _range2cols('A,C,Z:AB')
    [0, 2, 25, 26, 27]
    ú