def section_sep(title):
    """
    Add a comment that serves as a section separator and a title for human
    readability of the ultimate TeX file.
    
    inputs
    ------
    title : (str) title for this section

    outputs
    -------
    section_sep_str : (str) containing the separator comment
    """
    
    return  "\n\n%%\n%% " + title + "\n%% " + "-"*len(title) + "\n"