def METHOD_NAME(original_content, new_content):
    macros = []
    for line in new_content:
        if not _pattern_exists(original_content, line):
            macros.append(line)
    fmt_input = ''
    if macros:
        fmt_input = "\n{comment_line}\n{content}\n".format(comment_line='# content added by Leapp',
                                                           content='\n'.join(macros))
    return '\n'.join((original_content, fmt_input))