main funcion of visio2img

def main(args=sys.argv[1:]):
    """ main funcion of visio2img """
    if not is_pywin32_available():
        sys.stderr.write('win32com module not found')
        return -1

    try:
        options, argv = parse_options(args)
        export_img(argv[0], argv[1], options.pagenum, options.pagename)
        return 0
    except (IOError, OSError, IndexError) as err:
        sys.stderr.write("error: %s" % err)
        return -1