def remove_illegal_characters(src):
    """
        remove_illegal_characters()
        ________________________________________________________________________

        Replace some illegal characters by the underscore character. Use this function
        to create files on various plateforms.
        ________________________________________________________________________

        PARAMETER
                o src   : (str) the source string

        RETURNED VALUE
                the expected string, i.e. <src> without illegal characters.
    """
    res = src
    for char in ('*', '/', '\\', '.', '[', ']', ':', ';', '|', '=', ',',
        '?', '<', '>', '-', ' '):
        res = res.replace(char, '_')
    return res
